TCM 2, I grew up with it and watched it almost immediately after discovering TCM for the first time which was around 86' or so! Of the other sequels, using the term loosely, I've always liked Leatherface and enjoyed both the 03' remake and its prequel. Next Generation was definitely the worst but it sounds like TCM 3D is giving it a run for it's money; I'll make my final opinion on that one when I get it from Netflix!
A little Leatherface piece I did back in the late 80's!