Had a 600, don't really regret selling it, it was fun, but the parts that were likely to get broken or worn, were not available at all. I got mine from an Antiques shop near the city center of Montreal, someone had absolutely BUTCHERED the gas operations piston's outer surface, which required me to turn the surface down, and fit a sleeve to bring it back to dimension.
Still have a few Crosman's though, a couple of bulk fill per-cartridge era pistols, a couple 150's, a 38T in a factory Holster that still has the Mcleods store price tag on it, and a couple Mk1's. Lots of interesting things to be learned, once you start to delve in to the histories and variations inside the runs of certain models...