I am both seller and buyer. From both ends: buyers are way better protected than the sellers and there is a lot of room for a scam no matter how genuine seller you are. For other buyers: if your item came as not described, you can always start a case with eBay and most likely it will be decided in your favour. So there is no need to leave negative reviews - I guess many people who did that just don't know about these features. If the case is decided in your favour, you will be fully refunded and seller forced to accept return and charged full amount.
However, it does not work the other way round. In general, sellers are way more exposed than buyers - we can't even start a case against dishonest buyer and by default the buyer is always right. I've had few issues already despite being super transparent in my descriptions, posting high res photos of actual items + packaging, sending them exactly as described and my items are not cheap (1000+). And every time I am thinking - what will the buyer complain about this time?
The good thing about eBay is very accessible customer support: you can email, call and chat. However, the outcome really depends on the competency of the person sitting at the other end and they are not always trained to help you solve cases which are even moderately complex. I'd expect better service and better protection for the fees eBay charges you off every sale.
Still they are way better than Etsy and other selling websites although there is a lot of work to be done to make it really safe trading environment.