T-Mobile (NASDAQ:TMUS) has transformed the U.S. wireless carrier space into an ultra-competitive arena with its Un-carrier promotions and has left Sprint (NYSE:S) -- its closest competitor -- in the dust. 

As the nation's No. 3 and No. 4 carriers by subscriber numbers, T-Mobile and Sprint are locked in a battle for customers who refuse to pay the higher prices that come with Verizon Communications and AT&T's superior networks. Sprint has recently been able to slow what had been a mass exodus of customers, but it has yet to grow at the breakneck speeds T-Mobile has enjoyed quarter after quarter. 

Click on the following slideshow to find out how the two carriers performed in the most recent quarter and why T-Mobile again came out on top. 

Chris Neiger has no position in any stocks mentioned. The Motley Fool recommends Verizon Communications. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.