On iOS we regularly get into the Top 10 iPhone and iPad Sports apps (both top paid and top grossing), and on Android into the Top 20 Sports apps on Google Play.
Our WP7 version has generated approximately 0.5% of what our iOS app has made, or approximately 2% of our Android app.
We also have had a Mac version of our app available since July which has almost passed the total sales of the WP version which has been on the market for over a year (our app is primarily targeted at mobile device users while they're at a sporting event, so lower computer sales are expected).
The jury is still out on how our Windows 8/RT app will sell in relation to the others since it was released just prior to the launch of Win8 but after the majority of our sport's season had completed for the year.
Our app does spread pretty virally at the events. In our completely unscientific polling of users, most of them found out about the app from other users, and I would guess that those WP users probably just assume that it's not available to them (we do give it equal promotion with the rest of the versions on our website).
As far as the release of WP8 goes, we haven't seen any noticeable uptick in sales as a result.