So I'm warning you now before you even start reading this, I'm writing this while reconnecting my Series 2 and watching a second box give me the 8888s of death.
It's not all so bad however. Let's go back 3 weeks ago, to a simpler time.
We replaced an iGuide Comcast HD DVR and my Series 2 TiVo with the new Comcast TiVo. The install was, complicated. He came with only one box, when we needed two boxes because of some issues we were having with our iGuide box. So about 6 hours later we had two TiVos up and running. One worked fine, the other (in my room) not so much. It would lock up when using OnDemand, would randomly stop recieving signal, and go black until restarted, and then one day, about 2 weeks later it died flashing 8888s. I called Comcast and they got a tech out next day to replace the box and update the software.
All went swimmingly. The other box didn't have a problem and the new box also, painless. I recommended the software to a friend as well. I said that one of my boxes had some hiccups but now it was running well.
Now I should interject that "well" is probably the best way to describe it. It was never great, or spot on to the TiVo service. The tivo sounds would screw up occasionally and it was SLLOOOWWW compared to my Series 2
Anyways back to the story, about an hour ago we had a power outage and the box upstairs started right back up and my box again, began flashing 8888s. So rather then replace it again, and play Russian roulette with Comcast boxes I'm just going to go back to my Series 2.