I think that's a difficult question to answer. I happen to live in a neighborhood that Verizon brought FIOS into last summer. The population density is high and given our geographic location, I'm sure the ratio of tech-savvy people is pretty high (I'm in the Baltimore Washington metro area, and there's a huge concentration of high tech companies here), and there's been a demand for non-satellite competition in this area for a while. A lot of people have made the switch, including myself. As a customer, I was very frustrated with Comcast. We had continuing service issues, especially on the higher channels, that had never been resolved - the picture would frequently pixelate and freeze for seconds at a time. Boosting our signal, changing out equipment, replacing lines - nothing worked. In the meantime, our prices kept increasing. I'm paying $30/mo less for my FIOS service, including one box with DVR, than I did for Comcast's service. The picture quality is excellent, the channels are grouped in a sensible way (sports together, music together, etc.). Comcast has tried all sorts of ways to get me back - phone campaigns, mailing campaigns, special offers. However, they can't guarantee lower prices or better service than Verizon. Everyone I've talked to that's made the switch agrees with me.
From what I've seen, Verizon is targeting the areas that they feel will bring them the biggest payback in a short time period, and it seems to be working. I don't think you can say they moved too soon - they still only have approval in certain counties in this region to provide cable TV service, so Comcast still has a big chunk of this market. They're not making the infrastructure investments until the approval is given, so I think it's a well-thought out strategy at this point. My feeling is that Comcast has been caught flat-footed; they had the majority of the market for so long, they really don't have a strategy for dealing with this competition.