yup, only opinion, all about the fun...here's mine
well, let's look at this geometrically. again, i don't need to bump sales, this is about the fun of "bench-racing"...
i don't care where you drive the wheel from...ultimately, it comes down to stressing each individual spoke at a single point, right? well, think about it...properly installed, the gebe drivering actually exerts the (motorized) stress at a point that is more "wheel-friendly" than any hub-based drive can possibly be...by moving the point of stress closer to the rim, you've reduced the overall stress to the whole wheel assembly. the drivering fits the spoke arrangement very precisely, and serves to hold the spokes in their proper position better than a hub or sprocket can. it's mechanical logic.
and, because we're talking about weight and power ranges that are significantly smaller than any other vehicle, belt-drive makes sense. imo, any wheel that the gebe system would break wouldn't stand a chance being hub-driven.