I have a 1988 SR500, it looks like new, I bought it off of eBay maybe 2 years ago, been a fun bike to ride, Now if I was looking again I would go with a ST model, a little more relaxed frame, but Cannondale made some really nice bikes, looks and feels like a step above the other offerings.
I like what Rccadr does on his rebuilds, he puts together some beautiful machines.