Out of the 6 followers I've used so far (Lydia, Jordis, Faendal, Uthgerd, Benor & Jenassa) the winner is Jenassa, the elf mercenary I hired for 500 coins at The Drunken Huntsman in Whiterun (Faendal of Riverwood was the second best so far).

The worst ones so far are the Housecarls Lydia (Whiterun) and Jordis (Solitude).

Lydia must hate sneaking. Sneaking into a cave battle against a large unmber of enemies with Lydia is like using a megaphone to annouce your arrival & passing out maps of your location to the enemy just before you attack.
I'll be sneaking into a cave ready to shoot arrows to cut the numbers down before the enemy knows I'm there and where I am and before I can get the first shot off, Lydia goes streaking past me with sword held high yelling "I'll kill you all". All I can say then is ;- "Thanks Lydia, I always wanted to die".
Once the battle is on, she'll be fighting one enemy & I'll see another coming so I lineup a good shot and the instant I fire, Ldyia breaks off from her fight and jumps in front of me, taking the arrow for my enemy.
Ldyia has died numerous times and always from MY arrows or sword because she ALWAYS jumps in my way just as I swing or fire.
She always says "I've got your back" but she doesn't seemed to have realized yet that a person's eyes aren't in the back of their head.
Also, I always put my horse some place safe before approaching an enterance then start sneaking. Where is Lydia? 5 feet behind me sitting tall in MY saddle on MY horse getting it filled full of arrows. IDIOT!!

Jordis isn't much better except that when I go to my horse she races me & gets on first. When I make her get off and I get on, half the time she hops on again right hehind me so the horse won't move.

Uthgerd may have been a good bar brawler but she gets killed within the first 2 or 3 minutes of every fight. She's worthless

Benor may have a big ax and a powerful swing but his 2 handed ax is so slow that every third enemy kills him.

Faendal is good. He doesn't get in the way, too, often and he's a good archery trainer.

Jenassa the elf is good. She hardly ever gets in my way and then seemingly by accident while in battle. She uses 2 swords and spins them like propellers and hasn't even come close to dying yet. She never bothers my horse and when I sneak, she sneaks.

So far, she's the winner by far with Faendal a close second.

As far as sneak, they all sneak if you are sneaking?! Maybe they blow your cover because of heavy armor noise? I loved having Faendal as well, plus he is so positive but very weak. Even with enchanted armor and apparel he was always taking a knee. If you want a true follower, go get Mjoll the Lioness. She is the most powerful and cannot die!

Heck yeah, Jenassa! My Dunmer even married her she's so darn awesome. She's not too bad at being stealthy, either. A little macabre and grumpy at times, but I like that in her.

Other than her, I've tried Faendal, J'zargo, Brelyna Maryon, and a couple others that I didn't have long enough to really get a feel for them.

Faendal seems to be pretty good, though I've only just started using him. He tends to lag behind me a little bit farther than others I've tried, but he's saved my butt on more than a few occasions. And he's such a cheery fellow.
Everyone raves about J'zargo, but I found him absolutely annoying. And he kept getting in my way. It wasn't long before I dumped him back at the College and picked up Brelyna instead. I was a lot more pleased with her and found her much more useful, which is strange considering she doesn't "specialize" in combat magic and J'zargo does.

I've also had Meeko and Barbas as doggie followers. Barbas barked incessantly and kept trying to push me off cliffs. Meeko barks a lot, too, but at least he's not out to kill me, and he generally stays out of my way. At the moment, my Dunmer has both Jenassa and Meeko as followers. They're quite the posse.

Oooh! I love comparing followers!

I've used:

Lydia
Jordis
Stenvar
Faendal
Janessa
Benor
Argis
Calder
Marcurio
Vorstag
Uthgerd
Onmund
Aranea
Roggi
Mjoll
Belrand

Wow, didn't realize how many I've tried out until I listed them all!

I love, love, LOVE Janessa! She died this game and I'm still sad. She's my favorite.

I also love Belrand. This game was the first time I tried him, and he's so awesome my character married him. He never gets on my nerves, and that's rare.

Stenvar can be a tank with the right gear, but he is also a whiny baby. Complains a lot about the cold, dusty air, etc.

Of the housecarls, Argis is probably my favorite, and Calder is okay. The others I have not gotten on well with.

Mjoll is good but talks waaaay too much.

Marcurio is a good mage, but his chain lightening is a liability all too often.

So yes, Janessa is my #1, Belrand #2. I also think both have some of the best follower dialog bits in the game.

You have to know the role your follower play in the game. All the housecarls have the same skill set, and it doesn't include sneaking. Yes they will crouch into a sneaking stance when you do, but as soon as you attack an enemy, or if an enemy gets too close, they attck. If you want to sneak with a follower, use followers that have stealth in their skill set.

How do you know which ones have stealth?

This is a good resource: http://www.uesp.net/wiki/Skyrim:Followers#Permanent_Followers

Sorry for the double post, but edit isn't working right.

You can also make up for lack of sneak by using giving a muffle-enchanted item to a non-sneak follower who already naturally tends to stay back. This works well with Belrand and Faendal, in my experience, and probably with others. It's not perfect, but it makes them more useful in those situations.

Housecarls:

Argis - he's the only one who I really use a lot and who gets a major upgrade in gear.

Calder - used him for the first time with this PC, he would probably be as good as Argis with the same gear but there's something about the voice they used for him combined with the housecarl dialogue that annoys me. Also: muttonchops are not a good look for him, but as long as I keep him in a helmet and can't see them it's not too bad.

Lydia - hate with a burning passion, only use her when absolutely desperate for assistance and there's nobody else available and convenient (and I work hard to make sure that never happens). She may be a better combat buddy at higher levels but her VA makes her intolerable.

Iona - haven't had her out for a fight but recently interacted with her a great deal after getting the house and title in Riften. Also hate the VA for her so she is likely to stay home guarding my stuff.

Jordis - never used her, don't care for what little VA I've heard in previous playthroughs. Haven't acquired her yet this game but rarely stay in Solitude long or use the house there so when she comes along it's likely she'll also stay at home guarding my stuff.

Others:

Marcurio - totally awesome, except for aforementioned issues with Chain Lightning when other allies are around. Solved that in this game by removing that spell from his repertoire via the console and replacing it with something else he didn't already have. Will apparently use any staff he is given to great effect, snappy and varied dialogue that almost always makes me laugh, arrogant but with the skillz to back it up. Fearless in battle and never gets in my way.

Faendal - okay I suppose, used him a bit and he never got me killed but, overall... meh.

Stenvar - agree with the above, good tank if you gear him up but too whiny.

Erik the Slayer - adorable personality and attitude, pretty good in a fight for an "untried" warrior. Don't let that crap iron his pop bought him fool you, he's better in the light stuff and with a 2H weapon strapped to his back.

Benor - okay as a tank, didn't really have him long enough to assess properly. OTOH if I'd liked his company I probably would've used him longer, so...

Cosnach - didn't have him long enough to upgrade his gear, so I don't know how he does in a fight with better arms/armor. Probably worth a longer try just for the dialogue if his response to my healing spell is any indication. ("Hey... my hangover's gone!")

Kharjo - LOVE. But I'm biased when it comes to interactions with the Khajiit.

Golldir - used him for a long while at lower levels on last playthrough. Nothing special, but then I didn't upgrade his gear much and didn't have a mod yet where I could make him level up and "train" his skills as we went along. Still, he looked far too dorky in the horned helmet I gave him and I just couldn't get over it. And our repeated failures to take out dragons as a team made me ditch him in Riften and hire Marcurio instead.

Ulfric Stormcloak - obviously modded in, but certainly has the most joyous combat attitude and dialogue I've heard yet. Trash talker extraordinaire, leveled up via UFO and with gear close to my own quality he's a powerhouse. Also the only follower I've had while also using UFO that will dismount on his own to deal with passing threats while we are riding. I'm sure that's just because of how the mods are working together, but somehow it just seems so right for his character as a follower. Annoying if I'm just trying to sprint past a minor avoidable threat, but priceless if my back really *does* need defending while on horseback. I just have to remember to stay out of the way of his shouts.

Mjoll seems like she might be good as a fighter but I can see where I would get sick of her pvssyr after about five minutes, so I've never used her.

Interesting, so the DB initiates are the strongest at max level 100.

If you really want Jenassa (or any one else) back, just reload from your previous autosave & continue from there or if that would set you, too, far back just use the RESURRECT command (a cheat code) and bring him/her back to life, if you're still near her or know where her body is.

She died honorably, so I decided to let her go in peace. My character actually stood next to her body for a good five minutes while I contemplated reloading.

Also, one of the mods I'm using has the sad affect of causing followers to not like you if you resurrect them. They don't aggro, but they are not friendly. (It's one of the divorce mods, and the follower you resurrect will take on the same AI as if you bailed on the wedding. Don't know why it has this side effect. Something to do with factions, I imagine.)

I thought about uninstalling the mod, but I realized that I like that it kind of forces me to deal with things as they happen, you know? That's become my preferred play style. But I won't lie, I used UFO to make my husband Belrand essential. Did I mention that Stenvar and Roggi died also? A person can only handle so much death, even in a game.

Get the PRIMA Bethesda Official Game Guide for Skyrim. It has it ALL.

Most game guides are just under 1/4 inch thick but this guide is just over 1 1/4 inches thick (that's 5 times bigger) at 655 pages.
You get all the info on every weapon, shield, armour, spell, enchantment, character, location ,shout, perk, follower, upgrade and every thing else in the game as well as a large folding map that detaches fom the book to use as a reference.

The book is about $37 but it's very big and informative and it's very well worth more than $37 if you really like this game. It is rather expensive but I'm really glad I bought it. It's been of tremendous help to me & to my freinds.

I have it. It gets used daily, too. I got it on Amazon for $16, but it's worth the full price. And it's absolutely beautifully done.

Maybe it's not what you think. When you resurrect a follower they aren't being unfriendly, they're just not a follower any more unless you tell them to "follow me". Then every thing should be as it was before.

The first time I used it an archer killed my horse with a long shot while crossing a bridge. In less than 5 minutes I went to town & bought another horse & the same thing happened again at the same place. After 2 more times I'd had enough so I reloaded from before my 1st hourse was killed, started across the bridge, he killed it again so I ran across the bridge, killed him, went back to my horse, RESURRECTED it & continued on from there.

No, this is definitely different. My first character used no mods, so I'm familiar with what you are referring to. (And I used to accidentally kill followers often in the beginning, so I resurrected those wiith no issues.) But now with this mod installed, if I resurrect a follower, it doesn't open dialog when I try to talk to them, they say stuff like, "Oh, you want to talk to me after what you've done?". It's actually funny.

Did you marry the Hagraven, too?

I have to agree with the OP. I haven't used a lot of followers, but Jenassa was by far the best.

ps - Dude what's with the large font? You have a size problem?

Not on my Dunmer, but I have on another character. My Nord, I think is was. You're referring to the Hagraven during Sanguine's quest, right?

Some thing you may not know is, before your follower gets killed, one the the things you should select to say to them is :- "Accidents happen in battle. Let's forgive & forget" (some thing like that, it's one of the selectable dialogs you can use) and they won't get mad when you resurrect them.

Yep, that's the one.
That series of quests were halarious.

If you spend a lot of time reading & writing online your eyes can get tired & blurry. Larger fonts help prevent that.

That is not stock dialogue for followers, it's added by a mod, most notably UFO (or one of its variants). Unless the player is using the mod that adds that option, and it doesn't conflict with the divorce mod he/she's already using, this isn't going to solve the problem.

Hell yeah she's sooOOOoo damn good that Gorgun decided to take her hand it seems like her sneak actually sneaks like mine does, every one else gets me busted
I do believe her skill set is that of a Ranger so she kicks some major a$$, my close second would have to be Kharjo. He as well doesn't get me busted while sneaking and he's rather quiet and stays out of the way as well.

Well, since the larger fonts fit fewer words on a line, my eyes have to go back and forth too quickly with your posts. I’d like to read them, but they hurt my eyes. I can always adjust my settings if I want the fonts larger.

It’s similar with posts in all italics. I’m sure the content is as unique as the font, but I’ll never know since it hurts my eyes to read them.

More specific to the topic, Marcurio is a favorite of mine. He has the skills to back up his attitude.