CNET has a really nice breakdown of the newly announced TiVo Mini, including what it is, how it connects, and all of the reasons why you may or may not want one (assuming you’re already on the TiVo train, that is):
Similar to the Stream, the Mini feeds off of a TiVo Premiere 4 or XL4 DVR. Connect the Mini to a secondary TV and to your home network, and you’ll have access to live and recorded TV, video-on-demand services (for Comcast Xfinity customers, at least), or other broadband-delivered content through the main DVR.
Basically, it gives you a chunk of TiVo DVR functionality without needing to buy an additional DVR.
Included in the ups and downs are the fact that the Mini connects via MoCo (or Ethernet), but doesn’t have provisions for Wi-Fi; the fact that it uses the tuners built into your main TiVo for live streaming, but doesn’t do so dynamically, so each Mini you add permanently hogs a tuner that could otherwise be used for recording; and that it supports many of the apps built into the TiVo system, but oddly enough, not Netflix and Amazon Instant Video (the two I used the most when I still used TiVo).
Price on the Mini is $249.99 if you opt for the lifetime service, or you can drop $99 and tack an addition $5.99 per month onto your TiVo service fee.