My Local dealer has the R1200RS in, I took one for a 40 min test ride today on mixed fast and twisty roads. I did own an R1100RS, and currently own a R1100R and a F800GS.
I was very impressed with the R1200RS, the motor is very smooth and the standard exhaust has a beautiful sound, this is an area that BMW really seem to be improving. It was a dry warmish day so I left the mode set at Dynamic. Terrific acceleration, the dash is really clear and easy to read, tyre pressures clearly visible courtesy of RDC. For my 5'7" shorty size this bike is perfectly proportioned and comfortable. Biggest disappointment is the two position screen. In the upper position the wind protection is good, however much too noisy for my liking. Would be very annoying on a long run. I hope either BMW or an after market screen will fix this, then I would consider this a perfect bike for my needs.