Hehheh
Am a happy user of the Model M122 and F XT, and between them, I find no need for the SSK. I think SSK has a cool factor, but beyond that, is not superior to a Model F in key feel, or a Model M terminal in usability.
Portability? Hell, SSK is significantly heavier and bigger than a Filco TKL. And those professionals who do a lot of typing and moving around will prefer HHKBs.
SSK's the kind of keyboard I would buy at $150 for my collection, and would stay away at $250 and above. If you have so much money, buy a HHKB and customize it to the max and you would get something more mobile, equal in quality and key feel, and probably just as lasting.