Well, actually in terms of auctions Bruce and Rich are the exceptions here.... every other big auction house I know of (HA included) charges both a consignment fee and a buyer's premium. Those places take a slightly higher percentage of the overall item, but it gives the impression of splitting it up -- some from the seller (consignment fee) and some from the buyer (BP). It's fairly common practice, even if it really does result in a lower return to the consignor. Of course, you have to take final auction values into account... some items Bruce sells for more, some items HA sells for more.
While on paper Bruce and Rich's consigment fees might technically be higher on paper, after the BP the math does seem to work out well for the consignor in the end. And by not charging a BP, they also attract a lot of us cheap skates who feel like a buyer's premium is unfair (wait, I'm paying you a premium to pay you money?). In reality though, I just factor in BP and bid like normal. I've bought slightly more from eMovie than HA, and I've actually never won anything from Rich -- but I wouldn't discriminate from any of them if they had a particular poster I was after at the moment. That said, I'm a deal hound and buy the majority of my posters from ebay and elsewhere...