Nobody is even close to beating Comcast's availability + technology.
FiOS is up there (the technology may be even better than Comcast), but the lack of availability and the set top box issue I mentioned make it a no-go for me.
The three most popular and biggest internet providers in the U.S. are Comcast, at&t, and Verizon. I don't see any of them matching Comcast.
Also, Comcast's "coax" technology has been around forever and is already embedded in many homes from their original analog cable TV a while back. Now, they can use that same coax and bring internet and phone to the already-serviced areas that they've expanded into for many years.
The point still stands, if you had to move for some reason into a city not served by Comcast (and there are plenty of them) then you lose your Comcast address. And you can't honestly tell me that if you lost your current job and the only job offer you got was from a company in another city not served by Comcast - and it was great pay, great benefits and they were paying your moving expenses, etc, that you would turn it down because you might have to switch to U-verse or FiOS.
I work for one of Comcast's competitors, and one of the awesome perks is I pay barely anything for a bazillion channels, the fastest internet tier, VoIP with unlimited long distance (that bit's actually free - I wouldn't pay a dime for landline since I have a cell phone), and as many set top boxes as I desire, and that keeps me loyal to the product and my job, but I still won't use my ISP provided e-mail address because I'm not so loyal that in the event I lost my job that I would stick with them and turn down an offer in a city that would require me to switch to someone else.