First a little background, my quad was flying perfectly with APM 2.5 (Genuine 3D Robotics) using 3.1.5. After a while I began noticing all the uproar about the new Pixhawk hardware being much more robust and decided to give it a try. I purchased a new Pixhawk from 3DR, swapped controllers and proceeded to load up 3.2 on the Pix. I performed all of the calibration routines and they all went smoothly.
I then headed outside for some tests. It took off normally and seemed to hover and fly well. After flying around for a few minutes I decided to land and upon touching the ground it promptly jumped back up and flipped over braking my GPS tower and a couple of props. The next few flights led to the same results no matter what I changed in the settings. I became frustrated and took the Pix off and tossed it into a drawer.
Fast forward to now when I saw 3.4.4 had been released and for whatever reason I decided to give the Pix another chance and see of I could get it to work. I switched out the two controllers and proceeded to load up 3.4.4. Without a single piece of hardware being different,...same external compass/GPS module etc, same parameters as before to the best of my knowledge, viola, now she fly's like a dream. Lands just as smooth as the APM, holds rock steady in Loiter and is just very impressive now.
I am not sure why but from my point of view it appears 3.4.4 changed something about the behavior of my particular Pixhawk to make it a completely different animal. Not a single motor change, prop change, ESC change nor anything else occurred with the frame etc to justify the better performance. It is all the exact same equipment. The only thing I can come up with, if it is not the 3.4.4 code is maybe I had some sort of corruption that loading up 3.4.4 overwrote.
Oh well, mark me down as a Happy PixHawk user now.