Some changes i've noticed:
- it runs smoother than .30, really smoother, at least smoother. i noticed slow-ness when open quickoffice hd in power saving mode when it was .30, now with the same power saving mode, it's faster (like about 2-3 seconds), quickoffice is kinda a heavy apps i think, of course you won't have any problem in balanced or performance mode.
- new animation when open or exit apps, and i like it, of course the animation runs smooth too
- you can now disable the smartdimmer feature in settings->asus customized settings (thanks to jgaf he figured out this)
- because of google new voice search, we now have a new text-to-speech engine (the same as google voice search), and she sounds "sweet", the old one is gone, imo the old one sucks, can't really here anything, this new one is better than siri, sounds better, at least with the English US i believe.
- of course we have a new google voice search and google now, which is the feature i've been waiting for, help me practice my english

- looks like google has changed the "Tab UI" a little bit, for example: on .30 firmware, when you go to settings->apps you see "Downloaded", "Running", "All", to switch between these "tabs" you have to tap on them, but now with jelly bean, you can swipe left and right to switch, also the "tab menu" looks nicer (like windows phone i think)