A few minor system updates have been rolled out, i think last week or not too long ago, to fix many of these reports.
I'd say at this point, if you're buying one, you will be fine and receive a flawless product.
edit - a little sillyness but you're on the 2012 nexus 7 thread. if you want more assurance you can head over to the 2013 one.
Mytouch3g / LG G2x / Nexus 7 - 2012~CM10.2 (Official Nightlies) / Nexus 4 16g~AOSPA 4.4
Nexus 7 - 2013 ~Stock, Rooted
Black Nexus 5 32g ~Stock, Rooted