Tivo/DVRs - Pros & Cons?

[Nixxxed]

If you have Tivo or another DVR system, would you please list a few of your likes/hates about them?

Also, are there any stand-alone DVR systems yet, say that use those VCR codes encoded into TV shows? Or do you always have to pay for the service?

I'm seriously considering asking Santa for one. Commercials just keep getting stupider and stupider and stupider, not to mention there are increasingly more of them in any given show. Besides, I have a wicked surfing habit. I'll just sit-and-flip for hours until the show I actually want to watch comes one.