Articles like this one from CRM Lowdown that attempt to figure out who provides the best and worst service are always interesting; I don't think I've ever read one without seeing something that makes me say "Huh?" and this is no exception.
The article says it's measuring call center service, but I'm not sure that's what they're really doing. And I'm not sure that's a great measure; for example, American Express makes the top ten list, and when you call them, the service is excellent. Of course, their online presence is so embarrassingly terrible that I've actually stopped using their card much over it. I've never seen a major financial institution with such a user-unfriendly web site. Is this relevant to call center service? Given how much the article talks about the web, I would think so... but the authors never make it clear.
In the ten worst list, the item on "AT&T Wireless" is perplexing, and not just because there is no company operating as "AT&T Wireless." They're talking about Cingular, of course - and the article they link to talks about "Cingular," not "AT&T Wireless." (I assume this is because AT&T, having swallowed up BellSouth and assuming full ownership of Cingular, has announced that they're rebrand the mobile carrier at AT&T Wireless. They haven't done it yet, though.)
Once you sort that out, you find that the complaints about Cingular are generally not call center related. (No surprise; I've been a customer of Sprint, Verizon (when they were Bell Atlantic), and T-Mobile over the years, and found that none of them have particularly great call center service. I just can't figure out how the material provided to explain Cingular's ding is even relevant to the topic.
Strangest inclusion of all, though, is eBay in the "ten worst." eBay provides support online. That's pretty clear when you start using it, and it's one of the reasons that they provide their services so cheaply. Why not ding Yahoo or Google for this one?
What is most clear in this article is that if you're going to rank companies and make lists, you need to be very clear about what you're evaluating. Otherwise, rankings don't tell us much of anything.