Corsair Keyboard Mac

Easy; Razer. Cross platform drivers with cloud saved setting profiles.
Corsair does not have, nor will they ever have (their words) drivers for Mac. CKB is barely functional at best, and lags behind OS updates by about six months to a year. Also, if it bricks your keyboard, Corsair will void the warranty.
For me I'd really like the Razer over the Corsair.

As much as I like Corsair, none of their special features function at all on Mac OS X.