I got iDroneCtrl [a limited but growing GCS for iOS devices ] and it works really solid and seems very intuitive. I created a mission and it worked flawlessly. I think I might have to get an iPad just for this. It plugs directly into the lightning connector and has it's own mavlink radio. 100mv. Not great range but I flew around a local park and never lost contact. Mostly what it's nice for is creating a mission on the fly or if you don't have any other telemetry you can at least see you voltage, sats, altitude etc. Nice to see some options coming into the scene for Apple products. 

 http://www.fightingwalrus.com/products/idronelink