Upgraded to Lollipop the day it was released so here are some problems I have encountered.
Bluetooth keeps cycling droping out. I noticed this due to connect to my Wear Watch. Before Lollipop, I had no problems. Now it will drop the connection several times a day. This became more evident due to activiation of the Trusted Device option in 5.0. Setting up a lock for the lock screen (pattern, pin whatever) the phone unlocks with just a swipe if the watch is connected. If not than Ihave to enter my PIN, in this case, to unlock. All too often I have to enter my PIN becasue Bluetooth being disconnected at some time from when I last used the phone. Also, while in a call using bluetooth, the device will disconnect and re-connect in the middle of a call.
WIFI: I have WIFI turned off when I don't need it. Lollipop wants to keep turning it on for some reason and leave it on. I have tried several different changes in setting and nothing works. Never had this problem in KitKat.
LTE and Voice: Signal strength. Calls dropped in areas where I never had problems before. No internet connection errors more frequent than before when not using WIFI. No Data signal at all in areas where I had good connects with KitKat.