A note on the general battery life of R5 - I did an OTA update from R3 and left the phone on overnight doing nothing. In the morning the battery meter was down 20% wheres in R3 it loses 3-4% over the same period.
According to CPU spy in R5 the CPU spent ~60% of its time running at 1Ghz, 40% at 245Mhz and never entered deep sleep at any point. Both the built-in battery app and GSam battery monitor have 'Android OS' as keeping the phone awake constantly and causing 81% of the battery use (the rest being the phone radio).
On R3 the CPU spends ~98% of the time in deep sleep overnight, so it looks like one of the changes made in R4 or R5 stop the phone from being abe to sleep properly. I can't test R4 to work out which one as I get the reset/freeze problem that was fixed in R5.