I personly, this is only my second model. but I found the subD's are a bit slow to work with. Although I had a lot of luck converting back and forth with out making the poly mesh heavyer. but rather subD's or just smothed Polys. I was allways just going back to the base mesh and tweeking there.. gess poly smoth proxy is good also. that way there are not a crap load of verts to tweek. but thin you might be doing that anyway. becouse I still end up tweeking verts quite a bit.