Stuffwelike posted this video comparing the Xbox Smartglass app, which cross-platform, on Android and Windows Phone.
The main differences appear to be the integration of social features in the Android app, while they remain separate in the Windows Phone app in the Xbox Hub. Given the multi-tasking situation on Windows Phone this may in fact be an advantage on Android, as popping out of the app on Windows Phone to reply to a message will mean having to reconnect when coming back.
Otherwise the app is very similar, and it is interesting to see the Windows Phone UI being transplanted by Microsoft onto an Android phone so fully. Those Android refugees will feel right at home when they upgrade to a Windows Phone 8 handset in the next few weeks 😉