I managed to test the Altitude Hold and Loiter functions of my ArduPilot Mega2 controlled Hexacopter and was pretty impressed with it. There was strong winds initially but when it died down to a breeze I turned on the altitude hold and it seemed to hover with a deviation of around 3m. Then when I turned on the Loiter mode, my hexacopter stayed within a 5m radius despite some wind. The fact that I didn’t do any adjustments and used everything stock was quite impressive to me. The firmware and code is well written I guess.