Some apps and their live tiles don't work but OneDrive worked after a few tries!
Sometimes the phone locks up after using an app, you just need to give it a few moments (about 6 seconds) before it continues. I had a few reboots as well thanks to whatsapp.
I'm seriously thinking of reverting back to 8.1 and testing the preview on my 640. but first I'll try a hard reset and not touching the old Store. I think some apps get corrupted because they keep overwriting eachother all the time because of auto updates. Like the Weather and News app.
Great build still, 8.1 feels so... dated, old. Fast though, but I much prefer W10M by now, even with all the flaws :unhappysweat: