A tour operator here did a Trans-Africa eastern route (in just 2 months) a few years ago. Out of 8 bikes, 7 were 800/1200GS's and one guy was on a Honda XL700. That was the only bike with zero issues on the whole trip, the rest were being fixed here and there, and sometimes transported on pick-ups to get somewhere to be fixed. They only had a few days off from riding on the whole trip, and soon found out, that those were proper rest days only for the Honda pilot, and the rest were always trying to fix something.
That said, the tour leader still rides an 800GS, made a similar trip with it to the Stans last year, and thinks it's much more fun and more rideable on the dirt, than an XL700 (and I agree on that).