The problem lately is that there's more Chinese sellers than guys just selling off older spare parts. Even when there is something from a regular guy just selling from home, you get bombarded with all the Chinese crap first.
Of course, over the years, I've had more issues with dishonest buyers than I have with sellers overall. I shipped a new in the box motorcycle hub to a guy on the west coast and as soon as it got there he claimed it wasn't as described and wanted a refund. He shipped me back a box with half a brick in it and Paypal issued him a refund. I eventually got my money back after Paypal saw that he was returning every item he bought but if I hadn't had a perfect feedback score over so many years I don't know if my argument would have been heard or tended to.
The big thing lately is bait and switch scams. They show one item and ship something else, this combined with some creative photography, and you have a lot of disappointed buyers.
I've bought a few things from Chinese sellers, but only if there was no other option, out of maybe a dozen items two turned out to be total junk.
One was light bulbs, the other was a fishing reel. Both sellers eventually refunded me and told me to scrap the item.
The biggest problem is a toss up between sellers not having a clue what they're selling and sellers who have a completely different opinion of what is considered 'good condition'.
For me, if I'm looking at a saw, first and foremost to be in 'good' condition, it has to run, it shouldn't have any drop damage or broken bits, and it should start with minimal effort.
I've always been into old motorcycles, I can't believe the state of disrepair I find some bikes in. Missing parts, wrong parts, duct tape, hose clamps, and spray paint seem to be the norm lately. I've owned dozens of motorcycles, I've never once felt the need to remove and throw away any parts that it came with 'because they were in my way'. (Looked at a bike the other day that had no air cleaners at all, and apparently hadn't had any for a long time).
I looked at a four year old truck the other day, it supposedly had only 33,000 miles on it. The first thing that turned me off was the cheap steering wheel cover that didn't fit right so they wrapped it with duct tape. It had cheap camo seat covers, and it was missing both front arm rests, the console was cracked, the radio was dead, and they had some cheap Chinese air cleaner kit on it with loud exhaust. In the ad they described it as being 'low miles' and in immaculate condition. I've seen old farm trucks in better condition. My question was how on earth do you do that much damage to a truck with only 33,000 miles in just four years.
I think it sort of goes back to the low IQ thing, or maybe heavy drug use?
The way I've always looked at eBay, flea markets, or used cars for that matter is that people generally don't sell something they like or are happy with. They trade in their cars when they start becoming a problem or they need more money than they can afford to fix them. The same with anything else.
Most people don't get rid of a perfectly good running saw, they get rid of them when something about it made them move on to a new one.
Buying anything used is a matter of figuring out why they got rid of it in the first place and then deciding one whether its worth it to you do deal with that reason. In some cases that reason may not matter to the second hand buyer, but in most cases, they're dumping their problem on the next guy.
Personally, I've got a low tolerance for something that gives me grief, maintenance is one thing but if something doesn't do what I bought it to do, its out of here. I sell it, or return it and get my money back any way I can and buy something else.