We'll, I'm no expert, so I appreciate the link.
But to answer your question, I figured with all the pieces of kit sitting around my lab that get used once a year, there's a good chance that someone who values their chisel less than Superior Pneumatic does might have one that will serve my purposes.
Also, with most simple machines that have to stand up to physical punishment, my bias is for older models that are probably more solidly built. Then again, that's definitely a heuristic, and I'm far from expert in this area. Thanks for the advice.