For years, T-Mobile has been known mostly for its relative affordability, and a CEO who’s not afraid to wear leather. A new report on the state of US mobile carriers, though, shows its recent investments in infrastructure are finally paying off. Verizon and AT&T officially have some real competition.

The report, from OpenSignal, drew on data from millions of smartphones to gauge the speed of US carrier networks and how big an area they cover. T-Mobile has long excelled when it comes to speed; at over 12Mbps, its 4G speeds are on par with or, as of December, ahead of Verizon. (AT&T hovers just above 8Mbps, while Sprint’s 6.38Mbps may sometimes feel closer to 3G. Zzzzzzzzz.)

Where T-Mobile has made big gains, though, is in the breadth of its coverage. After years of being somewhat reliable in cities and pretty much nonexistent in rural areas, the carrier has crossed a major threshold. T-Mobile customers saw an LTE signal 81 percent of the the time in the fourth quarter of last year, just a bit less than what AT&T delivered. Yes, both still lag behind Verizon (87 percent), but it’s a level of saturation that lets them claim nationwide reliability.

For T-Mobile customers, though, being a close third here makes a world of difference. Lightning-quick downloads are great—when you can actually, you know, use them. That’s what makes coverage such an important metric. “It doesn’t matter how fast the LTE connection is,” says OpenSignal analyst Kevin Fitchard, “if you only have access to it 50 percent of the time, it’s not going to be a very interesting network for you."

T-Mobile’s ascendency shouldn’t come as a huge surprise to those who have tracked its recent infrastructural gains. Specifically, in January of 2014 the company announced it would acquire $2.365 billion worth of 700MHz spectrum (from, as it happens, Verizon). The 700MHz spectrum is significant because it has what T-Mobile had until then lacked: range, and penetration.

“Unlike its old LTE network, which is built on a higher frequency, this allows it to go out farther in rural areas, and punch through walls in urban areas,” says Fitchard. “What we’re seeing in the actual numbers is T-Mobile not just expanding out into more rural areas, but also improving its numbers inside cities.”

Having the fastest 4G network, combined with being available to 80 percent of the country, would be enough alone to place T-Mobile in the upper echelon that Verizon and AT&T have occupied to date. The carrier also, though, offers several cost-saving initiatives to its customers, like Music Freedom, in which streaming music does not count against data limits, or BingeOn, which controversially (because of net neutrality concerns) affords the same amnesty for streaming video on Netflix, HBO Now, Hulu, and more.

None of this is to say that you should run off and join T-Mobile today. Verizon remains the most reliable network, by a wide margin, and has recently become more cost competitive than you might remember. The same 6GB data plan that costs $65 per month on T-Mobile, for instance, costs $60 on Verizon. [Update As a T-Mobile spokesperson points out, Verizon also tacks on a $20 monthly "access fee" per line, making it effectively $80 per month].AT&T, too, offers good-enough speeds and plenty of coverage. More importantly, carriers don’t offer a uniform experience across the country, or even across a given city. The results of a national study doesn’t help a signal get into your office any more consistently.

A stronger T-Mobile, though, makes the carrier market that much more competitive. In an age when the two-year mobile contract is effectively dead, and technology makes switching providers easier than ever, having more choices to switch to should make all of them better, cheaper, or both.