I never received the OTA upgrage prompt from Google to upgrade my Nexus 5 from KitKat 4.4.4 to Lollipop 5.0 or 5.0.1. So I decided to do a fresh install of the factory image and boy do I like Lollipop. My battery life is noticeably better than it was on KitKat and that was my main complaint with my Nexus 5. I did the upgrade with my Windows 7 computer and everything went smoothly. I know that many people have experienced various problems with Lollipop since their OTA upgrade and I wonder if it's mainly due to an OTA upgrade versus a fresh install of the factory Lollipop image. I would suggest doing a fresh install and yes you will lose your data on the phone, but for me, I wanted to be running Lollipop and it was worth it.