I received mine yesterday that I bought to replace a Nexus 7 (2012) which 5.0 turned into a laggy, freezing, random rebooting piece of crap. The day before yesterday, I received 5.0.2 OTA update to my 2012. First day it seemed better, but today I'm already noticing lag and freezing and animations are very jerky. Did factory reset and any benefits are short-lived before problems return.
My 2013 N7 from Groupon arrived with 4.4.2. I updated to 4.4.3, then updated again to 4.4.4 KitKat. There is quite a bit of information out there about a memory leak issue that is crippling some devices OTA updated to 5.0, 5.0.1 and 5.0.2. Google has supposedly found a fix for the issue, but no details on timing of next update to 5.0.3 or 5.1 that should correct it. In the meantime, I'm perfectly happy using a smoothly running 4.4.4 KitKat build until a stable release of Lollipop is available. I have Lollipop on an N10 that runs OK but stability is more important to me than the few extra bells and whistles that Lollipop brings.