Root users get an easier way to access Jelly Bean multiple-user options
A bunch of users on the XDA forum post, and a few commenters on the Play Store listing do say that the app works overall, but we found it to be a bit buggy on both a GSM Galaxy Nexus and Nexus 7. That's to be expected. And, of course the underlying multi-user system in Jelly Bean is fairly thin, so you may not realize the difference when you switch users at first. Essentially, all it does is create separate user data for the apps on your device. Still, it's a pretty cool thing to play around with, and maybe some entrepreneuring developers can make more out of it.