I have bought and sold several items and had only one problem with somone who sold me a defective amp a couple of years ago. Like all internet commerce you need to make sure you know who you are transacting with. Disregard the ratings at Audiogon. The people who run the site make it almost impossible to post a negative rating because they believe it discourages people like yourself from using the site. I try to use paypal for all internet business because it protects buyer and seller...ie you can reverse the funds if something goes amiss. To me its worth the 3% charge and the convention is that the buyer pays.
