BMW makes wonderful motorcycles. However, except for the K1200LT, its stock seats are not comfortable and haven't been for a long time. I have replaced the stock seats on every BMW motorcycle I have owned starting with a new 1976 R90/6. Every one.
I have tried lots of different aftermarket saddles. My current favorites are those by Rick Mayer. Here they are on my R1200RT (left) and my R1150RT (right). Click on a photo to go to Rick's website.