I'm new to cell phones but I got the Nexus 5 and when Android 5 came along I backed up my contacts and apps, installed Android 5, and then did a factory restore. For some reason, I lost one contact--not a biggie--and two apps I'd purchased had to be downloaded and verified again. Since then, it's worked fine. I personally attribute this to the harmonic convergence of Nexus "5" and Android "5". Don't you see? It was just meant to be?
I would love an inexhuastible battery but I have a Qi charger on my desk and usually set the phone on it. Since I'm quite deaf I don't sit on the phone chatting for hours and have have no games on the phone so my battery will last all day. Also, it recharges faster than I expected. Not a lightning flash but faster than I expected.
Going from an Apple product to a Nexus has two problems. One is you lose cool. Everyone knows that Apple is cool and everything else, well, isn't. You also have to learn something. Everyone knows that Apple products are simply intuitive. Chimpanzes have picked up Iphones and called MIT within five minutes.
Other than that, though, Nexus 5 is, for me, great.