Having had hundreds of successful transactions on eBay, I must say that most eBay sellers are honest people who accurately describe their merchandise. The several bad transactions include one fellow who was selling fake merchandise, and another was a liquidator.
The liquidator shipped us a different package from what was described and photographed, even though his listing said "what you see is what you get". We wanted the electrical items that could be clearly seen in the photograph, but they shipped us a different package of electrical items, which were useless to us. I guess to them all boxes of random electrical stuff were the same. They stood behind their "all sales final", and would not accept a return. PayPal was no help. Shortly thereafter, that liquidator was bounced from eBay, so I suspect others had trouble with him too.
On other transaction, after a hassle proving the merchandise was fake (at our cost), PayPal rebated most of the loss.
There are several large X10 distributers on eBay. I have bought from all of them, and would recommend them to anyone.
Jeff