Here is the list of issues so far:
1) Device unresponsive while performing intensive operations - as reported on Venturebeat.com. Which seems to be similiar to an issue reported about screen responsiveness after play games, and as we all know games can be considered an "intensive operation".
2) Backlight bleeding which is being caused by device display not being properly screwed in, causing them to move or dislodge. Users have reported a squeaking noise around the plastic bezel.
It sounds like there may be a few rotten Apples in the first batch of Nexus 7's , which isn't uncommon for new devices. These issues may be easily resolved by a software update and a quick twist of a screw, so by no means do these reports indicate that the Nexus 7 is a failure. I am sure that by next week someone will be complaining about device temperature and battery life. You can read my complaint about the lack of expandable storage here