PC World: "For every hour of work, the keyboard makes some movement; it adjusts side to side within a space of about 1.5 inches. It also flexes and extends up and down to help promote blood flow. After about 20,000 keystrokes, the keyboard will move more frequently to help further mix things up. The keys vary in size, because of the curve in the keyboard, and to promote variation among your typing movements.
As a touch typist, I found the protoype keyboard felt comfortable, and the key positions convenient. I look forward to trying the real thing when its ready to ship later this year. The company also expects to offer a mouse, too, based on similar design principles."