I've gone to a few of "superauctions" and http://www.americanamusementauctions.com/ auctions which appears to be some of the same people or a new company or something.

Most of the pins are pretty worn. Sometimes there are nice titles, other times there aren't. I've stayed for the bidding and most pins seem to go around their estimated values. I'm guessing it is due to the buy-back policy in which owners bid the price up.

Once you tack on the 13% buyers premium (10% if using cash) and sales tax you're definitely not getting much of a deal. I've just used it as a chance to play some different machines on free play for an hour or two.