SV all the way...
I've been riding and doing trackdays for quite some time now. If I had to choose between those two I would go with the SV hands down. The aftermarket support is much more developed than the Ninja 650.
My first bike was an SV, then a ZX6, now an R6. I absoultely loved my SV and it was the perfect starter bike. I'm actually considering getting one again to start club racing.
What are the people asking for the bikes? I'm on the moto forums pretty much every day and have a pretty good idea of what's a fair deal for those bikes.