I just had my first stable loiter yesterday after running compasmot and it was very impressive. Tuning wasn't very difficult for the most part and the biggest barrier we have with getting more helis setup is the more complex cabling for the RX to the APM along with some radio changes. However there is something about seeing a traditional being flown by the APM that makes it seem so much more impressive when compared to a multi-rotor.
I also feel like I got away easy with vibration dampening, it's simplify some basic foam on the back of the heli shown below. My Accel_Z is +/-2-5, my Accel_X is +/- 1-2 and my Accel_Y for some reason is higher at +/- 4-8
I've noticed that I had to turn rate_p down a lot .55 on pitch/roll and I had to turn my altitude hold WAY down throttle_P .5 and throttle_I 1. Has anyone else had to tune in the same manner on those settings?