I'm happy so far with Jelly Bean in the few hours I played with it last night. The install even left my Adobe Flash install on the tablet which was nice to see. I did some sunspider testing pre and post JB install.

ICS

Stock browser - 1967
Boat browser - 2674
Chrome - 1377
Dolphin - 2126

Jelly Bean

Stock browser - 1008
Boat browser - 972
Chrome - 1447
Dolphin - 1168

Pretty weird that Chrome actually got worse ratings, but I rarely use Chrome since it's doesn't support flash.