The most prominent feature of this new model is its Sidekick-like form factor, although the U140 eschews the swivel screen for one that slides up to a 30-degree angle at the touch of a button -- all the better to watch programs from its integrated satellite DMB receiver (complete with TV-OUT).
All three perform the same basic function -- they let you stream TV from your cable box (digital or analog), satellitereceiver, or DVR to a computer or mobile device -- it's just that each is aimed at different segments of the market.
The Z-Base systems can be programmed to respond to most remote controls, so a TV remote...or cable box remote...or satellitereceiver remote...can control volume, mute, power and input functions.