With you there, Matt.
A tale from a conversation here in Aug/Sept on belts, chains, and Rohloffs, which I found interesting:
A very experienced cyclist friend north of Toronto put me in touch with some of his cycling buddies who wanted to move to touring bikes with Rohloff hubs. They are planning a supported cross-Canada ride in 2018. I referred them to Thorn's range, both Ravens and Mercuries, and gave them my positive review of the Raven-mit-Rohloff. (I did say that for their light loads, the Mercury might work better for them.)
As it turned out, they decided to opt for substantially more expensive custom bikes made by a builder north of Toronto, not far from where they live. He recommended the Gates carbon belt. My friend (and I) questioned the recommendation, essentially asking, "Is a chain a problem, especially with a 'glider?" And, "What about the other questions about the belt itself--tension, precise adjustment, lower efficiency, etc.?" The builder said that all those issues have been addressed by the latest versions of the belt.
This is very much an arms'-length story, FWIW -- but I'll be interested to learn how their bikes and their tour play out. I hope it works out well for them. Personally, I wouldn't pay the extra $$ for a custom bike, let alone the extra $$ for a carbon belt.