Just feel I have to add to this thread. Been a happy Nexus 7 2012 user until 5.0 came along, then wondered how on earth Google could push out something so bad. All the previous upgrades were no problem so I had no qualms about this one. Mistake! Battery drain during idle is dreadful, mostly due to 'android os', and strangely seems to kick in in the middle of the night. Battery saver mode makes no difference. I also have an iPad, and if I don't use it for a week then open it up its still at the same charge. Android always leaked a little battery on idle, but it was acceptable. Tried factory reset - no change. Just installed 5.1.1 (after reading some posts here) and if its still the same after, I will downgrade back to KitKat - or maybe sadly bin the device altogether and migrate to iOS. I believe devices should 'just work'. I don't expect to spend hours fiddling just because of a Google upgrade. Joining the ranks of the 'very disappointed'.