After using WM10 on my daily driver for almost 2 months, I have decided to go back to 8.1, as my 2.5y old Lumia 520 was behaving old with WM10, quick battery drain, a lot of hanging, loading issue.
But after going back to 8.1 my Lumia got new life!! super fast then any android, battery after 2.5y life still gives more that 1.5day, easy to use, its so simple even someone from non smartphone age can handle it.
I will wait for MS to release final WM10, then only I will decide again to update, till then sorry WM10.
Yeah I know i will miss a lot of features but those are useless if your mobile hangs a lot, quick battery drain etc.
So I need to compromise for some features as it is my main phone.