I recently rode a Multistrada 1200S Touring, and was quite impressed with it. It doesn't have nearly the comfort for touring that the RT does (Ie: no heated seat, no cruise control..maybe changing for 2013?, wind protection is lacking, rain protection lacking, etc.) but it's a great bike. And the motor is contagious.. to me, it made the C14 feel underpowered.
It's hard to beat the R1200RT for an all around bike, including sport riding, and touring. If I hadn't rode the RT extensively before getting on the Multistrada, I'd probably buy a Multistrada. But candidly, the RT has spoiled me, and I think it would be difficult to go to a Multistrada without really missing the RT.
The Multistrada is a great bike, but for two up touring, you can't beat an RT.