Ebay is great for a buyer. I love buying on ebay.
It is bad for small sellers. I've sold on ebay myself since 1999 and I find the friendly atmosphere and feeling of community you used to feel there has been on a rapid decline since about 2008.
My biggest beef is that there is no more authentic feedback system. A positive feedback left for a seller may not even be positive due to the detailed seller ratings star system. Most buyers probably do not know how much damage they are causing to a sellers account when leaving these 1 and 2 stars, and probably do it unwittingly. They don't MEAN to cause damage, but they do.
After three 1 or 2 star ratings, a seller can and probably will be banned, even with a 100% positive feedback rating.
Sellers are not allowed to leave anything but a positive feedback for a buyer, even if a buyer was difficult, abusive, unreasonable or did not pay, so there's no warnings for other sellers to heed. If you leave a message about the buyer in feedback that is less than glowing, ebay will sometimes remove it and warn you.
The last line of defense for a seller these days is to ban certain buyers manually, problem is, when you figure out who to ban, it's usually too late - they've already ruined your DSR or cost you in fees when you have to re-list what they didn't pay for.