It was intended to originally be a Cherry MX Clone of the HHKB, though you can get it with a true 60% case as well (control keys). Hence the name, KMAC
Happy. However, it's fully programmable (unlike the Topre board mentioned before), so you can make it your own. For instance, if the placement of some keys on the HHKB bothered you (like the Backspace and the ~), then you could reprogram those and have those keys be what you want.
Of course, there's the GH60 coming up, so the KMAC Happy has some stiff competition for American buyers. Plus, the GH60 is open source, so if you happen to miss it the first time around, you can make your own PCB and have a Post-production GH60!

Also, you could make the GH60 cheaper if you wanted to... $260 + International shipping + labor time is a bit much...