I have two Rohloffs, one with chain drive on my Thorn Raven Nomad, and a belt on my Jones Plus.
If I was going to do it over, I wouldn't go the belt route. It is very expensive to make any gear changes, the Gates belt sprockets and chain drive are pricey, plus you have to change the belt as well. And you should carry a spare belt, on any long tour. The little chain tensioner gauge is about $60 , I think. Its not absolutely necessary there is an app you can get for your phone, you pluck the belt like a guitar string and the app listens to the sound and calculates a tension. Its a bit flakey, but does in a pinch. I ended up buying the gauge.
As far as function goes , its great, I never have to worry about chain maintenance and the bike runs fine. Maybe it is slower, but I am not so fast anyway so it doesn't matter.
If drivetrain maintenance is very important to you, spend the extra money and get the belt. Although there are ways to get a long trouble free chain life on a rohloff -chainglider, etc.- so you don't necessarily need a belt.
The next Rohloff bike will be chain drive.