I hope for some good advice.

With my second char I've chosen to become a vampire, and it doesn't look good at all.
First of all My race is Kahjiit, and the pale texture of the vampire, as well as the eyes don't look very cool. As a vampire lord, anyway, the 3D model looks detailed but the wings don't move at all, and the rest of the body isn't dynamic at all. It looks like rigidly hanging from a rope, to be honest. Is that quest line worth the vampire lord choice? Because the more I think about that, the more I don't like the vampire race.
Thank you.

You esentially end up with the same ending and the same things in both questlines, simply not getting a crossbows with the VL.

It's both pretty much the exact same, only minor flavor differences.

I prefer the vampire side myself for some RP reasons.

Back when i was even more noobish than i am now, i chose VL side, and i was kinda disappointed.
Even after maxing out the perk tree and doing all side quests, the character and Volkihar faction just felt terribly shallow; sure vampiric grip can be invaluable when you are tansformed and can't use shouts, but there really isn't more to it.
Besides,

Only for RP reasons.

well, I think i'll be a fierce Vampire hunter then. Pity I already know all the quest.

if you want a vampire wife, or some enchanted gear for vampire lord, go vampire side.

If not, go dawnguard, you can still become a VL, and get the crossbows and everything, minus the enchanted accessories.

If your a mage go with the vampires,everyone else go dawnguard.

Only go Vampire if you are a hardcoe mage/vampire lord because you get some sixy items in radiant quests that pimp you out.

Well thieves and assassins get a good sneak bonus so I'd think some people would wanna go for that in itself.

That and many thief/assassin builds make use of Illusion as it tends to work rather well with the build. Vampirism offers the only permanent spell buff in the game.

Mainly RP is the only reasons, On my Assassin (Bows/Daggers) I went with the Vampire side and I RP her as only 100% loyal to Serana, Castle Volkihar and the Dark Brotherhood, every other faction she has an ulterior motive behind joining

My Nightblade?(Nord Destruction and One Handed Swords) I am using a few mods to make her different, one allows me to join the Dawnguard as a vampire, two the alternate start allows me to begin as a vampire (allowing me to RP as a character that is very, very old) and she generally wants to be a force of good despite her "condition".

There are very minor gameplay bonus differences (Jewelry to enhance Vampire Lord form or More advanced Crossbows and Anti-Vampire restoration spells) and there are some small flavor differences between the dawnguard and the vampires.

I enjoy the VL side, minus the numerous bugs. Also you're fully pimped out, perked out VL is a dark god that smooshes everything under the strange red glow that causes it to levitate (leviatation! boo to you Magnus!!).

You do know that you can't join the dawnguard as a vampire? There is a cut off point where they force you to cure yourself until then you cannot do any of their main quests or side quests.

Which is why I use a mod that lets me join the dawnguard as a vampire