Something interesting I discovered using Companions. At the moment I'm at work, so I can't double check it.
Whenever I used them they were aprox. 1 level apart from my player characters but there was one thing I noticed. They didn't have the right amount of skill points / talents. They were missing some talents (perhaps the starting 2? I don't know for sure) and skill points (again the starting 5?). So I got the impression despite the same level my companions were slightly less effective than my 2 player character.
Sorry that I can't provide hard facts, because I can't start the game.
