Speaking in general, a more moderate stance is the way to go for most lifters. As I add gear my stance gets wider. Also the use of a monolift would be a factor. For conversation sake, as most people are going to be raw lifters, lets stick to that.
From my experience most raw lifters rely on some rebound created with speed and a more narrow stance. BTB hits on a big point of the more natural position. If you walked up to someone out in town and asked them to do a squat, they wouldnt make their feet outside their shoulders.