I did a hard-reset to get the update, and that worked. Note, the phone will show the reset stuck at 0% even though it's not really, for quite some time. I had no issue with the reset other than that mostly cosmetic issue. (Putting aside the fact I had
to hard-reset to get the update....)
After the reset, my battery improved noticeably, but is still no where near my HTC One M8. As others have noted, something is going on in the background. Edge clearly shows the highest battery usage, even though it shouldn't (it's 35%, and the next is
15%). I notice that syncing with onedrive is inconsistent, and that might be part of the issue.
Just a thought, but I've noticed that Chrome on the pc eats my pc (SP3) battery, and really eats cpu cycles. I wonder if, since Edge is now a Webkit browser (right), if that is a Webkit issue?
Clearly, Msft needs to fix this. Stuff is going on in the background that doesn't need to be, and that is killing battery life. Hopefully they get this fixed.