eBay take feedback ratings very seriously. (If people don't believe them they'll be less likely to use Ebay, with a subsequent loss of profit for the company). The only reasons that your feedback can have been removed are given here:
http://sellercentre.ebay.co.uk/request-ebay-feedback-removal
Of course there are people who'll try to artificially inflate their ratings (e.g. by buying and selling lots of items using multiple identities, or in collaboration with others) but eBay generally spot such activity fairly quickly.
eBay ratings might be imperfect but they're probably a better guide than you'll get by buying at a physical auction, or on a market stall (for example), so it's unlikely that you'll find anything better when buying from a stranger.