Steinberg has released Cubasis 3. The mobile version of Cubase for iOS comes with lots of new features, many of which were requested by users. Cubasis 3 is a universal app, which also runs on iPhones.
FL Studio Mobile 3 is released on Android. The iOS, Windows App, Windows Phone and desktop plug-in version will be along shortly. That's mobile music making on pretty much everything.
Looks a bit plain but you can't fault the functionality of yMIDI - a Windows 10 Universal App multi-touch MIDI controller