I knew you would pull the defect card. I got the Nexus 7 as a pre order along with 4 other people. We got it as a gift for being the grooms man for my best friend. Every single one of us agrees that it just is not a smooth and fast device. My wife is not tech savy she felt it was sluggish and not that fast when I first got it ( this was before we got our gs3's and was coming from a galaxy s1 ) 3 of us are stock, 2 of us are modded. Mine also had a kernel that over clocked the GPU and it still lagged. I went back to stock and it still lagged, so I guess all 5 of us had defective units huh?
Everyone else here also agrees that the Nexus 7 was laggy. You seem to be the only one who thinks otherwise. I also don't doubt the GS4 lags, but if you thought the nexus 7 was smooth then I'm sure you would think the GS4 is smooth as well.