From my limited experience ( I only use it as an MP3 player - nothing more - not even video ) so far, I can tell

(a) The app appears to be more responsive

(b) There is now a single "main menu" instead of a multilevel menu, so it is faster to get to your media / plugin. What options show up on this 'menu' is configurable

(c) Once in a while you see glitches in the app - like a widget not showing or the wrong widget showing - This is more often than I have seen in the past - but not as often that it becomes a nuisance. And in most cases some screen refreshes ( i.e. moving to another screen and back) will make the problem go away and in certain cases an application restart is needed.

From what I can tell, there is no desperate reason to upgrade, but I did not have any reason not to upgrade either, and this way I will be on track for future upgrades as these problems get resolved.