Ok, so here is the low down. The Ceton card and WMC with LiveTV and record is AWESOME. Even the Comcast tech who came out said "wow, looks good". Very impressed with the signal and how easy it is to set up. The tech also mentioned that the diagnostics tool that Ceton uses was great and he really wished that Tivo had the same thing.
The bad...Comcast Tech Support on the phone are idiots on the weekends apparently. This was even noted it on Comcast own forum. After about 7 calls and having a manager tell me what I was trying to do wasn't possible....I posted on their forum and was told to email comcast cares and that the weekend employees were not trained for CableCards AT ALL. Within 20 minutes I had an email back asking me for my phone number. About 30 mins later a local tech called me who knew what the hell she was doing. She was the only one who knew how to actually pair a card. After all that it started working but none of the HD channels showed up!!!
So a tech came out this morning and he was like "the last guy who did your drop didn't do it right". He said there was a filter for basic cable and that my line had a lot of noise. He replaced everything. Redid the drop from the pole, replaced my cabling and redid the outside connections. Great guy and he got everything to work within an hour.
All that said, once it started work, it worked beautifully! The Network Tuner Sharing is so damn simple and just works. I have one tuner tuned to the PC in my office for my PC/TV/Testing. Two tuners to the Living Room TV and the last tuner in my Master Bedroom.