Never had an issue with standby/run time on battery with my N7. It had gobs and gobs of battery run time.

That was all before Android 4.2/.4.2.1 though -- some users report that things went way downhill on the N7 after that.

I sold my N7 a few weeks before the update, though (never figured out what tablets are good for, other than as a photo album), so I have no experience with it after the update.

Cheers