If you buy the app for iPhone or iPad you'll get a $10 off code to buy Mac version. There might be a free trial version to download from shredder website, try that also.
shredder for mac
You could do a lot worse than use the free stockfish engine with the free chessx UI. You can download current builds of both at www.box.com/chessx
Anybody own shredder for mac? How is it. Will it analyze my games better than the computer analysis on here? Is it worth buying the more expensive version or should I just stick with the computer analysis on here?