I have 5.02 available as of yesterday but I'm staying on KK. Most of the problems are persistent right up until 5.1.1 so I'm staying away until my carrier pushes that one. Current commonly reported problems for my device so far are battery drain, media volume reduction, lag, camera issues. Since I plan on updating this fall, my current phone will probably be replaced by the time all the fixes roll out anyway. Waiting 5 months for an incredibly poor OS update has me seriously considering leaving Android.
Good point above by the way. I agree with the folks who said a lot of the people saying their update is fine aren't aware that it isn't until it's pointed out to them so I take their feedback with a block of salt.