I wouldn't be surprised...
It has 5.0.2 on it now. I haven't noticed any problems yet, but I've only played with it a few minutes after the update.
I'm going to leave it unplugged today to see how the battery life is (with nothing much happening in the background).
There's no sign of when 5.1.x will be available for it (I assume it will be at least 6 months as that is how long it took 5.0.2 to reach me). :-/
I've never rooted an Android device, though I would like to know how to do such things, I don't really have the time to mess around trying a new/different OS on it. Here's hoping I don't need to...
Cheers,
Scott.