Experience and ability varies a great deal, but of course, they'll all represent themselves as experts.
Is there any chance you know of a cheat sheet of sorts for certain questions to ask when trying to choose between the good and the bad? I ran into this for a kitchen remodel (not the same, but you know) and it cost a ton to fix. We are thinking of laying some lines between the two stories in our home and I would rather not do something that a pro could do better, so I am in the same boat here.