I'm not trying to say eBay's great and wonderful, but it's really not all that bad!
I've bought and sold dozens of guitars through eBay, some ended up in face-to-face deals, but most were through the post. I've bought from the USA and Japan loads of times, I've sold to guys in Germany, Spain, Hungary, France, Poland..... a couple of times things have gone wrong and I've had to sort them out, but nothing's ever been seriously damaged or "lost" in the post. Ninety nine times out of a hundred, it works fine.
If you're the seller, you're doing most of the work so don't give the buyer any grounds for complaint, control all the things you can control - be honest, take good pictures, describe things accurately, answer questions (even the stupid ones), pack the things well, send them quickly. That's all you can do.