Ebay reputations mean nothing.
First, they can be manufactured. Just create a few hundred accounts, and then buy/sell small things between the accounts. Pay the ebay fees, which should amount to a hundred dollars at most. Always give top ratings and voila! you have a hundred sellers with high ranks! Then put a few expensive things for sale at very good prices, get a few sales on each, and you can get probably a few thousand high margin sales before anyone complains of not receiving the goods. Basically, make a million quickly.
And you can repeat the process many times if you are ambitious.
In addition to that many sellers selling fake, low total value articles (like a $30 BT headset) will include with the article a letter saying "we will post automatically a rating identical to the one you post". So if you give them a bad rating, you are getting one too, screwing up your account.
Based on my (and my close friends) experiences, the majority of products at eBay are either fakes or scams. There are many great sellers, but they are simply outnumbered by scammers. Many users do not detect the scams (they will blame the problems of a working but low quality fake to the purported manufacturer) and those who do will not dare damaging their reputations by complaining.
What bothers me most is that both problems are easily solvable. The first one by implementing a rating analysis system that detect such closed groups, or that weights the amount of a sale in the rating.
The second one by hiding one side's rating until the other one has been posted.
But apparently ebay is too happy counting the money. A sale is a sale, after all.