This is an interesting question and something tht guys have been talking about with units like the Guardian, iGyro, the Cortex, and others. One thing to consider with these units is that you are breaking the direct link between your receiver and your servos. You are now depending on the software (and hardware) in the unit to do what you want it to do, and even more so, when you hit the switch to "turn them off" in flight, you are asking them if you could please have control of your aircraft back. I have seen more than one occurrence of when the answer to that request is "no, you can't" - with predictable results.

We build UAV autopilots in my lab, and even after hundreds of flights, and many, many hours of testing, we still get occurrences of undesired behavior that we have to track down.

The technology is great, no doubt, but you have to realize that reliability is an issue. Personally, I'd only put a "proven" gyro on rudder (and nosewheel steering) and/or ailerons, but that's just me...

Oh, and I'd NEVER put any electronics by Hobbyking in the critical control path of a jet, NEVER EVER...