On Windows Phone, every app has the ability to offer a free "trial" version. So you can make a paid app, but still let the user try it (with less features, or ads). I think this mechanism is ideal.
Windows Phone has the best mobile programming environment there is. The tools are much better than anything you can find for iOS and Android. I know, I programmed apps on all major platforms.
So is it a developer success? I would think so. Is it a consumer success? Not really. But it's consistently gaining marketshare, and is becoming quite popular in Europe.
