You say you evaluated Cloudant and MongoDB, among others. Why did you decide on Cloudant?
-Recommendation by the Windows Azure team.
-Scalability.
-After I got my head around CouchDB in a weekend it was so easy I didn't need to look any further.
I used the documentation on the Cloudant site over that weekend so that definitely played a large part too.
High level -- what's it like writing for windows mobile vs iOS/android?
I've only just started developing for Android (Foundbite's next version) so can't really give an opinion. Visual Studio is great to work with though. There are only 4 screen resolutions for Windows Phone so in that sense it's easier to develop the UI.