That actually makes sense if verts only average their neighbors and not the entire group. The crazy method makes sure that is the case and if 3dsmax does that already then its just one big redundant step. If that's the case then the only other thing besides creating hard/soft edges & selection storage is like you said…
There aren't any major differences that I've found. The only real difference is that in 3dsmax you can assign bits of geometry to multiple smoothing groups. In Maya everything is assigned to one group and you can break edges or not. Multiple smoothing groups explained: http://www.fgiservices.com/Smoothing/Smoothing_05.html…