https://arstechnica.com/information-technology/2018/05/t-mobile-should-stop-claiming-it-has-best-unlimited-network-ad-group-says/

T-Mobile USA should stop claiming that it has "America's Best Unlimited Network," the advertising industry's self-regulator said today.

AT&T challenged T-Mobile's ads to the National Advertising Division (NAD), which ruled that T-Mobile hasn't substantiated its claim that it has the best wireless network.