I have bought hundreds of items on eBay with virtually no unresolved problems. Perhaps my suggestions on evaluating sells would be helpful to others.
1. Obviously, look at the feedback (I'm amazed that so many people buy from sellers with mixed feedback). DONT BUY if new ebay member, or very little feedback. Don't buy unless almost 100% positive.
2. If you are buying, check out the feedback on the seller's SELLS. Some people (like me), mostly buy. A crook can rack up a good number of positives by buying misc minor items. Then switches to selling and scams. Look at the actual items that have been sold to see if they are comparable type items. Maybe the seller only sold little stuff and now is suddenly moving into big ticket items. Beware.
3. Send an email to the seller, asking about some details on the item. If no response, don't bid. If the seller won't respond while he/she is trying to sell, what chance have you later?
4. If seller responds but answer is obviously incomplete or sounds questionable, either send another email or don't buy.
5. Especially for bigger ticket items, look for sellers that have been eBay members for at least a year. Beware of a seller with some positives, but less than a few months membership. Some sellers scam and then when the negatives pour in, move on to other identities.
6. If buying from a ham, check out his call on QRZ or elsewhere. See what the writeup is like, etc.
7. If you buy an item and run into a problem (shipping damage, item not as descrbed), be sure and make contact with the seller BEFORE entering negative feedback. Honest problems do arise, and the seller should have an opportunity to fix it before being hammered. Besides, threat of negative feedback does work to nudge some along. Once you post the feedback, that tool is used up.
8. My total experiences with eBay are very positive. Best of Luck. John, K0IZ