The Lumia Windows phones were actually pretty nice. App support was lacking but I have never been an app user. I would have kept using mine if the BlackBerry KeyOne hadn't come out shortly after.
I think it's common for former BlackBerry stans to go for unconventional phones to replace them. iPhone and typical Android phones are boring to me. I'm currently using a Surface Duo 2 and looking into a foldable as my next phone.