I have a Gen 1 S10 and just picked up a 2017 GSA on Thursday. I only rode it about 100 miles so far, but here are my random initial feelings/observations:
My S10 has Jesse Panniers, a heavy duty skid plate and crash bars so it weighs well above stock. I have about a 2" higher seat, 2" bar risers, and lower pegs. I am 6'7" with a 36-37" inseam. The S10 is stable as heck and feels long and tall.
The GSA without panniers (they can't put them on right now as you well know) and about 3 gallons of fuel feels like a sport bike in comparison to the S10. It actually feels small to me, way more compact. I could do super tight circles on the GSA immediately which is something I can do with the S10 but it takes more work. It just inspires confidence. I wanted to go straight to the mountains but had to get back to work. I will be looking for a taller seat, lower pegs and some bar risers for the GSA asap.
I could cruise with freeway traffic through Camp Pendleton (So Cal guys know what that stretch of the 5 is like) on the GSA no problem with little to no resistance or sound from the engine. The S10 just doesn't seem happy at that kind of speed.
The GSA is like a candy store to a kid. It is loaded with goodies and it brings a HUGE smile to my face when I ride it. The S10 is solid but has never made me feel the same way the GSA does when riding it. It just feels faster and sounds better.
The GSA windscreen is really floppy and kind of annoying. My S10 has a Madstad bracket and stabilizing bars so it is rock solid. The GSA windscreen is also way closer to me and that may be problematic because of my height. May not be able to get a taller windscreen that will get air over my head due to the closeness and angle (if that makes sense).
The GPS holder, specifically lock, already doesn't work and they have to replace it. It didn't work at the dealer before I even left. In addition, I got about 16 miles down the freeway and the computer told me I had two flat tires. I knew there was no way I had two flat tires but pulled over to a tire store and checked the PSI to be safe. All was fine. Called the dealer and went back and they apologized profusely and IMMEDIATELY replaced the sensors. I was back on my way in no time.
I am very wary of the reliability of the GSA from all of the horror stories I hear about so my beloved S10 is staying with me until I feel confident in this GSA. If I lose confidence in it I will sell it and go back to the S10 as I am not a roadside mechanic.
I can't say enough good things about BMW Motorcycles of Escondido. They were very fair to me and treated me great. Huge difference from my experience at the Yamaha dealers near me. Sure you pay for it, but I like to be treated well and not feel like I have to shower after leaving the dealership.
I will stick around this forum because it is a great place to be and again I am not getting rid of my S10.