I owned an 1150RT which I liked a lot. The only complaint I had was the removal of bodywork to do maintenance, and that it was not suitable for any distance on even smooth fire roads. I have always looked at the R1150RS when they popped up for sale, but I only liked them in one color combination. The GS was the same, I only liked it in two color schemes, blue/white, and silver. Long story short, along came a deal on a Silver machine with low mileage and fully outfitted. Sold.
This machine has full factory luggage, the BMW/Garmin Nav system (although now outdated), ABS, full service records, and a good set of TKC80s. It has plenty of usable power (and sound) thanks in part to a Remus exhaust. It is what I would have done. With that said, one of the auxillary lights has a broken bracket, the exhaust rubs against the luggage rack, and there are a few other issues to attend to.