ATT isn't a company you can count on anymore. They account for a very small percentage of ip transit. At one time before the isps starting to setup peering agreements themselves with other datacenters companies like att were alot more attractive since they provided connectivity.
Comcast/Adelphia used att in my area prior to comcast just doing it's own peering, now they have no need for ATT. As the larger isps have no need for att why would anyone else? You'll want to be where your customers are, closer to your customers, being with ATT isn't going to put you close to your customers.
ATT will try to use it's name to run with this service but the ATT name means nothing like it once did, it's a dinosaur that'll soon be extinct all together.