A pair of internal tuners let me watch/record two channels at once. And I've just discovered that the DVI output actually works!
Digital Video Interface is a digital alternative to a wideband component video (YPbPr) connection, which is analog. Using YPbPr, the cable box has to convert the incoming digital channel into three analog components. After receiving those three components, my Samsung 61" DLP TV has to re-convert them to digital. But with DVI — transmitted via a pricey special cable — the intermediate digital-to-analog and analog-to-digital conversions are bypassed. The result with an all-digital signal path from source to screen seems to be a slightly cleaner picture.
I must admit I'm a bit surprised Comcast's box supports DVI. Although DVI is digitally copy-protected, there's always the possibility someone will crack the protection and allow perfect digital bitstreams of the latest and greatest movies to BitTorrent their way around the Internet.
And wouldn't it be nice to be able to record those hi-def digi-goodies on, say, D-VHS tape? Not possible, alas, with DVI.
Still, the picture across the DVI interface is out of this world.