So the one big improvement I saw with Lollipop (I did a factory reset with the upgrade) was improvement in battery life. It lasts much longer than it did in KitKat, with one big caveat.
For some reason on my device (and I've seen this reported by several others), Bluetooth kills my battery if I leave it on, even if not connected to a device. Never had that issue with KitKat or any other device.
As an example, the other day I turned on my headset and talked for 15 minutes. I turned off the headset, but Bluetooth remained ON. At the time my battery was about 95% charged. Within 3 1/2 hours, I had less than 15% battery life. I thought for a moment I had forgotten to plug it in overnight or something. But when I looked at Battery Usage, Bluetooth had consumed over 55% of my battery in that short time since the call.
I'm not sure why this is happening, but now after I use bluetooth I turn it OFF on the phone and I get remarkable battery life. But it sucks to have to turn it on/off all the time.
Anyone else having this issue?