I'm currently riding a Trek 800 sport (big tires, big seat) and I'd like to switch to a road bike before the ALC next June.

I had been considering buying a used bike to train on for the next few months then invest in a bike early next year to finish training.

But I was told today by someone at my LBS that buying a used bike off something like craigslist is a terrible idea since most of the bikes have been worked on and people are selling them b/c they don't know how to fix them.

Is this just LBS salesman talk? Has anyone found and purchased a used road bike happily (or unhappily?).

Thanks!