heh, i've bought and sold loads of stuff on ebay, including a JCM 800 and never had a problem ever, in over 3 years & about 40 sales from all over the world.
Its pretty safe if you use your head and some common sense... the only people who get scammed are the ones who jump in and take every auction\person on there at face value! (and yeah stupid\naieve people aswell... no offence to them!).
With 2nd hand stuff you get as much comeback as buying from classifieds or a shop... and alot of ebayers offer returns policies now.
Dont fear the ebayer!