is it good or not? and try to keep spoilers low

Dishwater dull, just like the Fighters Guild from Oblivion. The only bright spot is the "transformation" ability, but it's acquired very early on in the story. The quest line can be prolonged if you play a few radiant missions in between story missions, though often the story missions are forced after only one or two minor quests. The villains are just "bad people" which translates to bandits with unique weapons, most side-quests have more fascinating enemies. Bethesda should really think about having the people who make their Thieves Guild/Dark Brotherhood quest lines do others, or perhaps it's the same people and they somehow think that warrior & mage quest lines should be boring and uninspired?

By "Companions" do you mean standard followers or the actual Companions guild?

i know i just saw thant and i ment the guild

Eh. I was unimpressed with their questline to be honest.

There needs to be emotional connection if you want a quest line's "dramatic twists" to have any impact. Considering you just met these guys and have talked with the majority of them one time isn't going to cut it.

Ultimately, the Companions serve as a glorified optional game mechanic more then a questline in their own right.

I kept waiting for the twist in that storyline and it never came. So disappointingly vanilla, especially compared to the thieves guild a d dark brotherhood, both of which were very good.

I liked the college of winterhold storyline, it was just really short. You become archmage like a week after you get there.

And these are prefect examples of the series getting dumbed down.
Even though people don't wish to admit it, they start to realize it little by little.

OT:
Well, I think that they are fine.
It's actually first fighter's guild I've joined (previous ones simply didn't attract me to them).
You will also get access to master level trainers to Heavy Armor, Two-Handed Weapons and Smith, and expert level trainers to Archery and One-Handed Weapons.
So yeah, if you hero relies on swinging his weapon a lot, then Companions is a faction you wish to join.