They been battling the battery issue over several of the latest builds and its not working. I upgraded to WM 10 on my Lumia Icon and its been a mess.
8 and 8.1 were stable and snappy. 10 has been a nightmare for me. The UI is nearly unusable and clunky. Just to do simple things, I have two, sometimes three additional clicks to get where I want to go. Even with successive builds my Lumia still freezes, crashes and restarts A LOT.
A typical example was this week. Went to my nieces hockey game with a full battery. Went to take a video, it started recording, then froze, then restarted (crashed). I thought, "Well, that sucks." It reboots, I try again, same thing. Then when my phone restarts, and I get the warning, "Your battery is critically low, please plug in."
I decided this week I'm going back to Android, Windows Mobile 10 at this point is almost unusable for me.