It's interesting, I left the MAXX HD because of lag and was told it didn't exist. I'm glad to see it's finally being acknowledged.
As I understand it, the lag is NOT caused by Jelly Bean itself. There is actually a Motorola power saving script that kills performance to save battery and that is the source of lag.
Example: the HTC First. Even though it has that Facebook homescreen, it can be disabled and the device runs stock Android and virtually lag free; and it is not as powerful as the RAZR HD.
My point is that a smoother experience is possible on a less powerful device. TouchWiz creates a HUGE performance hit on Samsung phones, which is why they seem to lag a lot. The Motorola script causes the RAZR HD lag. It sucks, because I really enjoyed the MAXX HD (except amoled, which the Moto X phone will have the S4 screen, ugh).