Harley switched their big twins to belts in the mid-80's and their Sportsters in the early 90's. I'd say belts are ready for prime time.

I've owned chain,belt,and shaft driven motorcycles. The belts blow the others away. The only time I've ever adjusted the tension on a belt was when I changed the rear tire. No lubing/changing oil,no cleaning,nada. And they put zero wear on the pulleys(sprockets).

A belt/IG hub combo wuold be perfect for a commuter or touring bike. If the hub could handle it,it prolly also would work for most MTB's.