The question, then, is whether the Das Keyboard Professional is worth the $129 price tag, since you can get a brand new Unicomp buckling spring keyboard for $69 and a vintage Model M for as little as ~$30 on eBay.
Frankly, I'm a little torn. The Das Keyboard has a lot going for it: the looks, the compact footprint, the USB hub, the Windows keys, and the more comfortable action. However, I may well switch back to the Model M once I'm done writing this review. Perhaps I'm just too used to the IBM keyboard, but I'm not convinced the Das Keyboard is a hands-down superior choice. And somehow, the ringing bothers me more than on the Model M.
This is a bit like trying to pick between two slightly different flavors of delicious ice cream, though, and I think anyone turned off by the Model M's size, looks, and clunky action definitely should consider the Das Keyboard Professional. Yes, it's expensive, but mechanical keyboards typically last longer than their dome-switch brethren. (Cherry rates its MX switches for a "minimum" of 20 million strokes each.) Divide $129 by, say, ten years, factor in the extra comfort and possible health benefits, and the pricing suddenly doesn't sound so crazy. Besides, Metadot offers a 30-day money back guarantee in case you're not completely happy with your purchase.
There's a case to be made for the blank Das Keyboard Ultimate, too. If you want to learn to touch-type, then a very comfortable keyboard without key markings seems like a great option. It's the same price as the Professional, and it'll let you impress your friends with your elite typing skills (not to mention annoy anyone who tries to use your computer).
I give Metadot kudos for producing a keyboard that differentiates itself from the Model M while being just as compelling—if not more so in some ways. Should Metadot produce a fourth-generation Das Keyboard, I would suggest the following changes: get the price tag under $100, make the key caps just a tad bigger and taller, lose the glossy finish, and try to dial down the ringing a little. Oh, and offer more than a one-year warranty. I think that's a little short in light of the price tag and durable key switches.