ignore seller's claims about how many/few miles it has been ridden. take it on a test ride of at least a half hour (and walk if the seller refuses, but offer to leave your ID or something), and inspect all the components yourself. some people can do more damage to a bike in a few hundred miles than someone else does in a few thousand miles if they take care of it properly.

good luck. my last two bikes have been CL acquisitions and both were marvelous deals!