After reading about all of the issues with the Lollipop update, I had been putting the update off for as long as I could. But one night, I woke up and the update had already started, so I was stuck with it. Anyway, before even messing with Lollipop, the very first thing I did was a full factory data reset. The phone works and runs perfectly and the battery is just as good as it was on KitKat. Now, I can't say a FDR is the answer since I didn't even take the time to run Lollipop without a FDR, but I can say that if you have the time and patience to do a FDR, you should have absolutely no issues with Lollipop. I get that it's a pain, but you can back up and restore and it's not the worst thing in the world to clean out your phone anyway.