Just installed the latest Android P version. Pretty smooth, for now, can't really say for battery usage.
I've just noticed a bug with the built-in Camera app (Nokia) which can't see the SD Card so can't save photos on it, just on internal storage.
by the way, application says "please insert sd card" though it's there and available for other apps
same issue here from last update..
It would be fixed via update meanwhile this may help you find the alternative solution to the problem.