We haven't had a chance to fully test this product yet, but we've assembled this helpful overview of relevant information on it.
Das Keyboard Model S
The Model S by Das Keyboard integrates mechanical key switches. These key switches are quiet and bear no inscriptions. A model of this keyboard unique to Mac (Model S Professional) incorporates Mac-specific keys.
Mechanical Key Switches
Mac-specific Keys (Model S Professional)
Linux, OS X, Windows