I've put 100k+ on a '12 and currently have 11k on my '15. If I was buying now, I'd probably go for the Gen II, having experienced both, but $9500 is a tough price point for a Gen II right now.
The Gen I bikes are not quite as smooth, but otherwise not that different. I upgraded my suspension after 100k, so I just moved that strait over to the Gen II bike. The Gen I bikes need the new cam chain tensioner before 50k if it hasn't been changed already. That's a part that was superseded, not just changed, so only one CCT is in the parts system. The clutch changes on the other hand, do make a difference and are not superseded parts, but rather new parts listed for the '14 on bikes. The earlier bikes retrofit perfectly, but the parts for the '12/13 are still in the system, so you have to order parts for a '14-on bike to do that modification.
As others have said, the factory CC is very nice and well integrated. I use it all the time. I had a throttle lock on the '12 and used that a lot too, but the CC is sure nicer. I didn't think the stock suspension was bad on the '12, just under sprung for riders north of 200 pounds. Especially traveling with a load or two up. A spring cost me $100, so it wasn't that big a deal.
You could spend $500 on a Gen I bike and be pretty darn happy with it. You could spend the additional $1500 or so on suspension and perhaps be happier than on the Gen II, but it would never be quite as smooth as the Gen II bikes. Both bikes get smoother over the first 5-6k miles. It's really noticeable on the Gen I though.
