Well, I can speak a little bit here. I am a current comcast subscriber and used to work for Roadrunner.

I have had @Home for a long time and they recently changed me over to comcast. For the most part it has been very good service. A couple of glitches here and there, but overall a reasonably good service.

I use a router instead of purchasing the second IP. Basically the idea is that this box will take the incoming DSL/cable connection and route it to the computers connected to the router (which also acts as a DHCP server and gives IP addresses to the connected computer). The extra feature is that this router is a wireless access point - so I can connect wirelessly to the network.

Overall, Comcast.net is a good deal. A little pricey, but a decent service. Don't forget you either have to buy a cable modem (something like $99) or rent it from them. Also, you will need to buy a NIC card for each of the computers.