Ratings are easy to tweak on ebay. Just sell a few cheap one dollar items for 90cents and you rating will be sky high in no time.
Remember rating of a 1000 dollar item is just as important as a 1 dollar item.
A low rating for a certain deal could still mean the item is perfect and exactly as described. . . . . . .
. . . but communication was terrible and shipping expensive and very slow.
A low rating like above for a common item would mean you should move on, but for a unique item there is no risk buying it from such a low rated seller.
Also remember that really unhappy buyers that open a case against the seller will not be allowed to rate the seller after that case is closed.
All in all a week old fish smells better than the ebay rating system.