I can't really convince myself to recommend the 4.2 update for Nexus 7 to you guys. It kind of breaks a lot of things that worked nice and new features aren't worth it.
Most of all it breaks autobrightness, lowers performance a little bit while bumping battery consumption, lock screen widgets aren't useful and it's a pain to roll down the notification pane instead of the toggle pane if your thumb isn't long enough.
Also, you are likely to get at least one joke about a "broken" lockscreen clock. Oh and amongst funny things, there's no December (yes, the month of December, it's not on the 'month' lists).