My experience with AuctionSleuth largely mirrored eee's. I liked the background searching features, but AS can lock up any system. 20 second response any time you change the focus between windows is to be expected. It constantly pegged one full processor on my rig. The performance alone renders the product unusable.
The clicking was also annoying. Every time AS does something in the background the user is subjected to a series of clicks... I found no option to turn that off. There is no way I could ever make this my primary eBay search tool with that endless clicking noise, even if the performance were radically improved.