I'd have to say the mounting loops/clips are the #1 thing that I'm snobbish about with IWB holsters. I carry at 1-2 o'clock and like some forward cant and there are precious few holster designs that fit in that location (need a small footprint in the belt, so no hybrids and usually only single clip works) and of those that do, even fewer have a rigid and firm enough clip setup to keep the gun from sliding on the belt or having the cant wander. It's so specific because I prefer bigger guns for carry (I shoot them better) so concealment under a t-shirt needs a more specific body forming setup. Only holster I've found that "gets it right" is the Vedder light tuck, largely because of the steel clips they use. Also, I hate having to adjust a holster every time I sit or stand/I want it to stay all day where it should. I can't do leather because in the summer I'm just s sweaty guy and hate soggy leather against my body, eventhough I always wear an a-shirt between my skin and holster. Oh, and I don't think anyone suggested that yet in this thread. Wear an undershirt, lots less rubbing and chafing that way.