I've been using the current iteration of Windows Phone/Windows Mobile (NT kernal) since November 2012 with L920 however my windows mobile journey started approximately 16 years ago with a candy bar phone running windows ce. It's UX was pretty woeful but it had a trackpoint and a full xp era start screen but then it stopped working but couldn't find a replacement. Since then I've used many phones and nothing comes close to in terms of UX potential to Windows Phone.
Out of the many phones I've had over the years I still have my E61, HTC Touch Pro 2, Samungs Omnia Pro B7610, the monochrome Nokia 3510, Sendo M550, Blackberry 8520, Lumia 920 and currently using a L930 with my old L930 as a audiobook / media player.
I started using phones when we used to save work on floppy disks and I'm 29 now to provide the context how fast we gotten to a point where a usb the save of 2 pence coin has the storage capacity of 64 Gigs and yet Icons have remained stagnant since the days of the Xerox Alto (1973).