The Beta version of Auctioneer* available from the home site, Scans fine and has worked extremely reliably for a couple of weeks now, at least for me. It also does a sort of "mini-scan" when you enter an item to auction, whereby you click the UIRefresh button. It then does a fast scan for prices of that particular item, and even signals the mini-scan is done with a burst of choral music, heh.
* auctioneerpack-3.9.0 available at http://auctioneeraddon.com/dl/AuctioneerComplete/