Here's a list of advantages I see the TiVo Series 3 DVR having over the Motorola DVRs that Comcast issues:
* Fast forward and rewind work more reliably and naturally on the TiVo Series 3. The Motorola boxes tend to have problems sometimes stacking-up remote commands.
* The TiVo will not re-record an episode if you've seen in within the last 30 days (unless you tell it to do so), while the iGuide software in Motorola boxes will record episodes marked new, even if you recorded that episode earlier in the week, watched it, and then deleted it. (This is common with shows on FX, TNT, USA, Sci-Fi, Lifetime, BBC, etc.)
* You can direct your TiVo to record programs from a website interface, as well as from the built-in program guide. However, note that there are indications that Comcast is getting ready to offer this service themselves, perhaps, though, for all their DVR customers. So that would be, at best, a wash.
* We, at least, have noticed a lot fewer SPDIF audio problems with the TiVo than with the Motorola boxes.
* The TiVo has 250GB of storage at a minimum, while the Motorola box has 160GB of storage at a maximum. The TiVo hard drive can be updated to over 1TB, and the TiVo apparently supports eSATA extended storage, while neither of those things are true for the Motorola boxes.
