I'm not familiar with the C-Tuner, but this tuner blows away the old software tuner I had been using. It's got a lot of cool vibe as well! I also had an email from my support tech at Peterson. He saw my post here and wanted to clarify that repurchasing the software after a couple of installs is not required. He assured me that they will accomodate the needs of any registered buyers.
Judging by the level of support I received the other night, all will be fine. Hope you get your Mac version soon Jules