T-Mobile has been found to operate America’s fastest wireless network a number of times over the past couple of years by several different surveyors and reputable market research firms, but when it comes to the “best unlimited network”, AT&T claims an objective titleholder is yet to be named.

After careful deliberation, the National Advertising Division agreed with AT&T that some of T-Mo’s most bombastic publicity slogans could be interpreted as misleading and unsupported by irrefutable evidence.

As such, the NAD’s recommendation is that the “Un-carrier” discontinue its “Best Unlimited Network” advertising claims, at least until it’s able to prove its unquestionably superior speed is backed by similarly high-caliber coverage and reliability.

In response to AT&T’s accusations and the NAD’s query for clarification, T-Mobile basically attempted to argue data speed trumps “coverage or reliability in evaluating a network.” Also, that its speed advantage over all other major carriers is in fact “so great that it overcomes any disparities in other network measurement categories.”

But the National Advertising Division ruled that, in order to qualify for an all-encompassing, indisputable “best unlimited network” title, a US wireless service provider must supply top-notch talk and text products, as well as support “high-speed data more reliably or to a greater coverage area” than everyone else.

In the absence of hard evidence confirming all that is valid as far as T-Mobile is concerned, Magenta may need to come up with a different advertising catchphrase. Of course, the NAD’s “recommendations” are not coercive directives, and T-Mo has already filed an appeal with the higher NARB (National Advertising Review Board) regulatory body.