I finally rebuilt my ATG-700-AL Hexacopter, and got around to moving my QAV500 over to the Graupner receiver.  Now that both platforms were functional, I decided to get stuck in to 2.9 and hott-for-ardupilot. hott-for-ardupilot is some code and user hooks to send telemetry data from APM back to the Graupner transmitter, its fairly light, and Graupner has a fairly well documented protocol.  

Graupner is no stranger to most non-US people, but has very little penetration in the US market due to lack of distribution (i think).  I have been thoroughly impressed by the build quality of the TX, all the components are firmware upgradable via USB and windows software (hooray vmware).  Following the instructions on the hott-for-ardupilot wiki, and putting in the extra UART headers on the APM, things were very much plug and play.  

2.9 compiled with the hott-for-ardupilot module without issue, after firmware was done, i reset both boards and proceeded with the 2.9 first run process (level, then accelerometer calibration). Of note, the mission planner UI button didnt work for me, it just stuck on "Initializing APM", however using terminal worked without a hitch both times.

The hexacopter has a camera gimbal, it took me a while to figure out how to make it work right, as the instructions on the wiki and the settings page in mission planner isnt exactly straight forward, but I eventually figured it out and got it pretty spot on as far as the bubble level was concerned.

Both maiden flights on 2.9 were straight forward, the hexacopter required no auto trimming, it was solid. The QAV500 took quite a bit, about 5 minutes of flying to trim it out correctly, but the autotrim function worked great. When I re-armed and took off it was solid (as you can see in the vid below)

Please excuse my N00b flying skills... Im still pretty fresh with flying!

Hexacopter:

QAV500 Quadcopter:

Overall, my first impressions of 2.9 are awesome, its a great advancement for the project, and im sure all the developers are excited by this.  My thanks goes out to them!

You can find the build posts for both projects on my project blog.