I have 8317 on my CCPM on both my VIBES. I switched from 8311 servos, in both setups I ran Duralite 2800 mah Packs with the 5.3 Volt regulator. Elsewhere on the machine I have a JR 7000T/8700G on the tail, and an 8700G on the throttle.
I made the switch on my first Vibe to 8317 back in June, and I immediately noticed the difference. The higher speed on the servos was more than noticable, mainly in terms of the cyclic response. I cannot say that I noticed a significant change in the collective. I continued to fly the machine with the 8317 and when I flew the machine with the 8311 still installed, my timing was off. I since made the switch to 8317 in both machines and love the servos. I would say that I have close to 20 gallons through the machines over the summer with these servos and no failures or noticable issues.
Overall, it is a very stable and precise servos, combined with the additional speed was a definite improvment. The only ting left to take full advantage would be to run the servos at 6 Volts (they are rated for such voltage and produces max speed). I have the setup to allow me to run them at 6 Volts, while keeping my Gyro down around 5 Volts and will try that this spring when the weather warms up in Indiana.
Hope this helps, feel free to email or PM with any more questions