I've rented GS's three times in Europe and have ridden a friend's pretty extensively. They're a bit of an acquired taste, but once you acquire it, you find them to be truly great bikes. They have an overall feeling of light steering yet great stability, especially during braking and bumps, that is quite confidence inspiring once you get used to the different feel. I think it is due to the telelever and longitudinal crank layout. The engine is a bit of an agricultural lump, but especially in the last few versions, it works really REALLY well.
I've never ridden a S10, but I've ordered one and I'm sure I'll love it too. People who think one or the other of these fine bikes is completely superior are mostly just tootin' their own horn for their personal preference. They're just different - a German and a Japanese interpretation of the same basic specification with extremely similar capabilities. I'm sure I could be happy on either, but the much cheaper price of the S10 (at least in the US), along with Yamaha making some of the most solid and reliable products out there (in contrast to BMW's "mixed" reliability record) carries the day for me. If the price were the same though, I'd probably get a GSA - where I ride (remote areas of WA, OR, and BC) with fuel stations hundreds of miles apart and often randomly closed, having huge range is just such a wonderful feature. I'll probably be carrying supplemental fuel bottles on the S10.
- Mark