I ride with the San Diego BMW MC club most weekends even though I ride a KTM SDGT.
Honestly I would suggest you ride a few before you make the decision. The 1200 has been around a long time and is a great motor slung low in the frame aiding center of gravity. Any GS 1200 will have zero problems keeping up or gapping the 1150r on sporty rides.
I don't know what the depreciation floor is for a r1150r but the 1200 bikes are aging well and hold their value well.
We need pictures man!