A friend got a WinPhone 8, he said it was okay. Then he upgraded it to Win10 and totally hated it. It felt really slow and buggy. For example it completely messed up the contacts list, it showed random profile pictures instead of the correct one from ActiveDirectory/Exchange in his business environment. Needless to say that company stopped the WinPhone experiments and stayed with iOS and Android devices.

Another friend really liked WinPhone 6.5 back then. And I have nice memories with WinMobile 2004 too. But that was the WinCE branch.