Just to add to the YouTube performance discussion. I've been regularly installing CM10/10.1 nightlies since they 1st became available several months ago and have had no performance issues (though there was a slight but manageable drop in performance when initial 10.1 was rolled out, I believe due to inability to use the native Samsung nvidia2 graphics libraries bundled with their ICS release or some such thing).
Yesterday upgraded from the 20130211 (4.2.1) to 20130218 (4.2.2) using the built in update function and the overall performance degradation was very noticeable with increased lag between pressing a key on the virtual keyboard to it's display, through to YouTube videos being being unwatchable (my demo clip is the latest Star Trek Trailer).
Wiped the tab and reverted back to 20130211 and the problems are gone and the performance is back in the 'usable' area again.
Thought I'd mention it as there seems to be some dispute about the validity of the various 'My tablet has slowed down since 4.2.2' claims. Just want to add that as a regular CM10 user I am also experiencing these issues and as such will have to refrain from further upgrades as it makes my tablet unusable
Should add though I am extremely grateful to Pershoot and the Cyanogenmod team for the work they are doing with this tablet, without which I would not have the joys of Jelly Bean and Google Now of which I am a great fan.