Updated my Note 10.1 to Jelly Bean and am very happy with the speed improvement.
There is a new bug though. If you have wi-fi turned off and the screen off, the screen will turn on and turn off every 20-30 seconds or so.
Solution is to leave wi-fi on but so much for saving battery life.

Anyone else have this error?

Another irritation is that when you take the s-pen out of the dock a note saying it has been removed stays in the bottom notification area and stays there preventing the use of the the pop-up until the note disappears which takes about 5 seconds. Too slow!