For some reason no one has remarked on one of my biggest problems with Jelly Bean - that Google no longer lets you opt-out of being tracked. There are two location services, which used to be called coarse (uses names of nearby Wifi networks and such) and fine (GPS). Google now won't let you use coarse without also opting in to having your location sent to Google at all times, whether you are using any application or not. So, for example, Google Maps doesn't work unless you opt in to being tracked at all times. Google Now doesn't work at all unless you opt-in to being tracked at all times. Etc.

In prior versions of Android, being tracked 24/7/365 was a separate checkbox you could opt out of while retaining full location functionality when you desired it, e.g. for Google Maps. No longer.

No one in the press seems to have picked up on this unadvertised feature change of Jelly Bean.