It feels smooth to me. Battery life is HORRIBLE though. Sucks battery like there is no tomorrow. I had 30 percent battery and put it on my dresser last night. under IOS6, I would have gotten up and had most of that left. However, it was completely drained this morning. During use (no wifi) yesterday, it used up 90% of the batter in about 3 hours of use. I think all the cool new 3D stuff is likely too draining for the 4s.