so I used, and really liked, my Lumia 800. Sadly it didn't get the upgrade to the shiny goodness of later Windows Phone releases so I jumped ship (many of the apps I wanted were available on WP8, but all of those devices were bigger than I wanted). Now I'm using an Android device and while it's okay I still miss my Lumia (especially Here downloadable maps and decent Email/Calendar integration)
I did try the Nokia X - Android dressed up as Windows Phone in a package virtually identical in size to the Lumia 800 (thought the corners on this new thing are ridiculously sharp) and though I liked the form factor and the bits of the UI skin that worked the thing was horribly slow and the screen resolution kinda reminded me of playing Chuckie Egg.
I really hope the merger does well. Windows Phone is the underdog, and that's where Microsoft does best. It also stops Apple and the Android ecosystem from relaxing and that rising tide raises all ships