When developers of successful iPhone apps look to branch out to other platforms, at the moment they naturally turn to Android, which has a much larger market share.
Steven Troughton-Smith, an indie developer living in Ireland, has just discovered that this may be a mistake. His cross platform 99c app, Speed, which is a GPS speedometer designed for in-car use, is clearly doing much better in the Windows phone 7 marketplace than the Android Market, where it apparently only has 10-50 installs. In fact, in the whole Transportation category, the top paid app has less than 10,000 installs, despite the supposed 50 million Android installed base.
The example underlines again that, if you are intending to charge for your app, Windows Phone 7 is already a better bet in many cases than Android.
Speed for Windows phone 7 can be found in Marketplace here.