Here are some excerpts from the site's description:
Despite its unique action, the Pianet is performed in much the same manner as most other electric pianos. Users may find an unusual feel that derives from the adhesive nature of the hammer and reed connection, resulting in a sound that is somewhat warmer and perhaps even grittier in the bass register, albeit just as bright as iconic instruments such as the Wurlitzer 200 in the treble register. The instrument's envelope, which is damped immediately with the release of the key lends itself well to more staccato or virtuosic passages. The Pianet is activated simply by turning the power switch located to the right of the keyboard to the 'on' position. The Pianet does not feature built-in amplification, nor does it incorporate other additions common to other electric pianos, such as a sustain pedal.
The Pianet is a highly unique instrument within the context of classic electromechanical instruments from the 1960s and 1970s. Whereas most fell into a singular category - such as the Wurlitzer 200 and Fender Rhodes electric pianos, the Hohner Clavinet, which was an example of an electromechanical clavichord, or the Baldwin electric harpsichord - the Pianet merged aspects of several different designs to offer an unparalleled sonic quality and feel for the player. Significant variations were made between the two basic groups of Pianet in 1977, with earlier models implementing stainless steel reeds, a pick-up with variable capacitance, and leather adhesion pads finished with urethane foam, and later models implementing spring-steel reeds, basic electromagnetic pick-ups, and molded rubber adhesion pads finished with silicone oil. In addition to changing the tone from one that was much richer in the earlier instruments to one that was decidedly more mellow in later instruments, the latter were also rendered more stable and easier to maintain. The leather pads of the earlier models required regular replacement as the urethane foam degraded over the years; the silicone-finished molded rubber pads of the later instruments were much more reliable. The silicone pads also had the added benefit of not affecting the metal reeds, allowing them to better stay in tune throughout temperature changes. The Pianet developed from Hohner's first electric keyboard instrument, which came in the form of the Cembalet, an electrically amplified harpsichord designed in the 1950s by Ernst Zacharias, who had a keen interest in modernizing early musical instruments. While still in the production phases of the Pianet, Zacharias developed the Clavinet, an electrically amplified clavichord, which stands as the company's most successful electric keyboard instrument.
I'm skeptical of the site's claim that the keyboard in Three Dog Night's "Joy to the World" is Pianet, however. I've seen some sources that say it's a Wurlitzer, and I think that's more likely.
