This was reviewed by chessreviews.com about 3 years ago (the PC version), and according to them: "[â€¦] I currently use Shredder for 90% of my analysis tasks, and it is my "first choice" engine. This is not simply because Shredder is strong. I think more importantly, I've yet to see the engine do anything that is really stupid, and the engine plays very patiently and consistently. [â€¦]" The interface is often praised as well. I personally find the interface clean and easy to use, but looks dated and could be improved significantly for the Mac. The current PC version seems to be richer in features (although it costs the same). The Mac version lacks an automatic update system, for instance. As far as I know, for the Mac, the only strong competitor to Shredder would be Sigma Chess using the HIARCS engine. At $20 is not a bad deal, but I wish Mac users could get the full feature set available on PCs and an interface worthy of the Mac platform.