I'm with you. Windows Phone is not bad, and the UI is better than iOS and way better than the confusing mess that is Android. Windows 10 that is,Windows 8 phone was a bit spartan.
I do a lot of mobile websites and UI work, so I like to keep track of what the frontiers of design is. Which is why I carry a iOS,Android and Win Phone device with me and sometimes swap out the SIM card to use the other ones as my main phone. I really like Windows phone but as a day to day phone I still use my iPhone. Why? a) Apps. b) Build quality. c) The windows phone always has finger smudges on the screen. It is little details like that that distinguishes Apple from Microsoft.
Before anywone accuses me of being a MS fanboy, I puse a Macbook day to day and an iPad. I very seldomly use Windows, except to test Websites with Edge (which is quite nice). I really do not like Microsoft on the desktop.
But for general handling of a mobile UI?? Microsoft all the way.