I purchased one of these from Aeromicro to use on a Demoiselle I built from RC Microflight plans. I just finished the plane and it's had one flight. (sorry, no pics yet) Obviously, I can't say anything about the longevity of the gear box, but it certainly runs smooth and quiet. A couple of tips: Don't trust the friction fit on the motor casing. On mine, the motor started spinning inside the plastic friction ring. I solved the problem by using some 3/4" shrink tubing just over the edge of the plastic friction ring and down onto the motor casing. A drop of CA at the front and rear of the shrink tubing locked everything up tight and I can still separate the gearbox from the motor if needed. Perry suggested limiting the prop size to nothing over 8". I used an APC 8x6 prop with some creative bushings to accomodate the 2mm prop "shaft" (a 2mm screw). I used some tacky glue on the screw threads when installing the prop to keep the motor torque from unscrewing the prop shaft. (don't ask how I found out why you need to do that)
Assuming that this GB has reasonable life expectancy, it certainly opens up new uses. We could build multi-engined planes with motor/gearboxes that could actually fit in a nacelle. No more relying on DD motors with high amperage/thrust ratios.
For those of us who are flight skills challenged, the box certainly looks like it could take a 9G landing better than the standard GWS gear box.
One final point. You will need the GWS micro gear puller set to change the pinion gear. Sart the pull with the largest diameter pin, and then finish the extraction with the medium size pin. DON'T start with the smallest diameter pin like I did!