There's a ton of discussion on this topic over on the RAZR MAXX HD forum. Reviews have been mixed on both sides. The general feeling seems to be that Jelly Bean does not really provide much of anything in way of improvement, at least not enough to make the few small problems (and some people did have much bigger problems) worth the up rev.
I did the update and I run Nova Launcher as well, although not the Prime version yet. For me I noticed no difference in performance. If anything I found performace a little worse with the stock launcher but with Nova it seems the same. Battery performance has been about the same for me, maybe even a little better. Some claim worse.
It seems that most that have posted have noticed things either a little better or a little worse, at least that's my feeling. Since things ran so well under ICS my feeling is why change for little to no benefit. But I've already made the change so I'm going to live with it. Hopefully some tweaks will be forthcoming to make things even better with it.