eBay gets a bad reputation with a lot of people for the reasons identified in this thread. And I'll admit it has its own unique problems. But I think most distrust in eBay exists because the Internet is still this nebulous thing that will always be to some extent new to everyone who was born before it was. We shouldn't kid ourselves; few stores are perfect, including nurseries and I would almost bet that this guy does the same stupid stuff at his brick and mortar store. I conduct a lot of business through eBay and I usually have pretty good luck with it. My worst experiences have actually been as a seller, not a buyer, because I can't choose who buys what I'm selling.
Here are some of my typical assumptions about eBay:
* Feedback isn't reliable, because people in general are rock stupid.
* People are more likely to leave positive feedback if they get the wrong thing than they are to leave negative.
* For 100 or less feedback,
anything less than 97% positive should be considered highly questionable.
* For more than 100 feedback, expect 99% or higher.
* Obviously, near 100% positive feedback is always highly preferred.
* Feedback of Chinese sellers should not be trusted, because too many of them fake it.
* Don't buy from China or Hong Kong unless you could lose the money and not care at all.
* Chinese sellers are never selling real antiques. Never.
I agree that it's more complicated to buy plants and be sure you're getting what you ordered though. It really is a crapshoot, so what's important is to make sure the potential benefits outweigh the risks. In other words, don't buy there unless it's just a good deal for some reason. For instance, it may be because you haven't been able to find the same item locally or the price is just fantastic. I've bought rooted crape myrtle cuttings there and they've been the cultivar I ordered. There's not a lot I could have done about it if they hadn't been, because it took me a year to verify it. But there really are honest sellers on eBay. The trick is finding them.
I think a good way to start would be to look into the reputation of the brick and mortar nursery run by the seller. If they have a good reputation in person, they're more likely to care about their reputation on eBay. Buying while the plants have leaves is another way to lower the risk of the purchase. Usually, I don't purchase plants of high value there unless I can see pictures of the exact plant I'm buying, taken while it has leaves.