Read original post by Colin Eberhardt at ScottLogic
Windows Phone 7 and the Silverlight framework are a great pairing; they allow you to create beautiful Metro applications with ease. The excellent tooling, coupled with the Nokia partnership, should make WP7 a big success.
Will we see a future dominated by WP7? I doubt it, and the analysts at Gartner seem to agree, with their 2015 predications indicating that Andoid, WP7 and iOS will all still have a significant market share for a few years to come. If you are developing a smartphone application this means you either make a choice between one of the three, or you have to write the same application three times, once in each of C#, Java and Objective-C.