I just bought a used R1150R which is basically the same bike as the Rockster. I used ot ride a ZX9R. I don't miss the top end pwoer at all. I'm actually suprised that it "only" has 85HP. The low end and midrange power is excellent and feels effortless. At speeds under 110mph, it will keep up wiht any sportbike at 8/10ths pace a do it effortlessly and in total comfort... and on rough pavement, I think it will outperfrom most anything else out there.
The fuel injection is very smooth, the gearbox is below average and I'm still learning how to shift smoothly on it. The combination of wide gear ratios, dry clutch, shaft drive the torquey motor make shifting a little less smooth compared to a sportbike. Awesome brakes and almost no brake dive from the wacky front suspension. The motor is supremely smooth between 2200-3700RPM (50-75mph 6th gear) where it likes to be when crusing. There's a nice surge 5000+ if you need it, but there's a enough torque that I usually upshift early.
Passenger ergos are awesome and it feels like it actually desiged for a passenger. A little floaty, but not too soft in the rear end, remote preload adjustment knob as well.
Overall, it has to be one of the best do-it-all motorcycles out there. Part sportbike, cruiser and touring bike all rolled together. I have detachable side cases and a top case, heated grips, and a midsized windscreen. I can't wait to load up for a week long ride.