Well tried both the new 690SM and 950SMR today, with my wife as she was considering a change from the GS. Here's what we thought - sorry its a bit rushed - I hate typing!
690SM. The missus hated it. Weord really as she loved the 640. After about 5 miles she kicked me off the 950 and we swapped over.
Initally I hated it too, but we had atest-ride booked so I percervered. it took a while but after blasting back home on my favourite twisteies faster than I ever have done before I thought it was loads of fun.
Its much smoother than the 640 but still unmistakably a big single and vibes still abound but on a much more acceptable level. It feels jerky at low speeds as the throttle is very snatchy at low-revs and the brakes are so powerful. On the move it really brings out the worst in me, as with all singles you have to really wind-it on and then the thing really shifts. Grip and cornering are totally confidence inspiring, the thing just leans and leans which means you can carry so much speed through the corners, sit the thing up and head for the next one, lean it over and hammer around. The brakes are awesome although the back brake is a bit full-on, maybe just seems that way as the rear brake on the GS is so pants.
It'd make a great second/third bike for quick blasts, but the rock-hard seat and wind blast over 60/70mph would make it a pain in the neck even for a decent half-day ride.
Loads of fun, I have one if I had £6k knocking about for a third bike - which I don't
Oh - it sounds rubbish, its needs the full Akro system on there - another £1k maybe?
950SM. This was much more like it! Loads of good smooth power on tap, I imagine it could wheelie for fun in every gear, and despite its extra weight and bulk (it feels almost as heavy as GS - which is about right considering its 8kg lighter) it handled nearly as well as the 690. Much comfier than the 690 and I guess it's be up to longer rides, maybe with a better saddle and a screen, but as stock it seemed that its place ina garage is as a second/third bike and not an everyday bike. I'd hate to sit on motorway at 80 for more than 10 minutes on it.
Overall, much, much better than the 690, but not as much fun on real twistes. Still not as accomplished as the GS but a lot more involving....maybe a little too involving for my missus as her only bike, so she's sticking with the GS for now.
Both great fun bikes that would make fantastic fun/alternative bikes. If I was after such a bike I think I'd go for the 690, but that might just be because I spent more time on it than the 950.
I would say that the Superduke must be the motorcycling equivalent of being wired into mains electricity. Sure, R1, Gixxer thou et al are quicker but the KTM is just so direct it's unreal. 
