I've never tried belt drive, so I can't comment on it. I can comment on chain drive. I've never had any trouble with it. If you keep the chain lubed and adjusted they are reasonably quiet. It's also easy to change gearing. I'm also not crazy about the idea of a bolt-together frame. If you consider the parts spec on the Monobelt, the belt drive comes at a premium of about $500. That's a lot of money for something that has not been proven and possibly still has some kinks yet to be worked out. I'm sticking with chain drive for the time being. I go though a chain and gear set a year on my Monocog, and I pay about $80 to replace them.
That being said, if belt drive bikes prove themselves I wouldn't be opposed to buying one
I am not repeating myself I am not repeating myself!