The KMAC does not use the AIKON firmware IIRC. The Cheat was on the AIKON, thus allowing PS/2 via bitbanging(I think) what would be interesting is if somebody ran the AIKON firmware on the KMAC since you can assign the matrix in the AIKON client. Herm....
Oh also, the Cheat has a funny story why it comes with a CMA key.
Aesthetically, the corners on the Cheat are rounded while the KMAC is not. Also, the Cheat case is an aluminum-acrylic-aluminum case while the KMAC is all aluminum. Also,the Cheat came in half plates and poly-carbonate etc, where the KMAC came with an integrated into the case aluminum only full plate. (I think that covers a bit of it)