Test rode 650s twice this year for about 30 minutes the first time and an hour the 2nd. I did like it but:Vulcan S. Trust me on this. Go eyeball one at a dealer and fanagle a test ride. You won't be sorry. Sweet, sweet engine. Plus, adjustable ergos from the factory.
1. Has little rear travel and that mono-shock is awful! Ride it in any stock configuration and you will be miserable in less than 30 minutes. I know I was.
2. Ergo fit: Don't help much when the seats are like most stock seats which is about the first thing you have to replace.
3. Too lite weight for interstate I was blown all over the road.
4. Accessories are slim to none at this time.
Just go to the Kawasaki Forums and you will see that most owners are looking for new seats almost immediately. Terrible freeway bike as it just don't have the weight to make for a comfortable bike.
That being said I was impressed with the 650S in many ways and if you are going to use it as a commuter around town with the now and then use on the back roads it's great.