Grading the top U.S. carriers in 2013's second quarter

second quarter 2013 earningsThe second-quarter reporting season is wrapping up, which mean it's time to sift through the data and see which mobile carriers slipped and which managed to get ahead. Research firm Strategy Analytics has compiled major metrics--such as churn, ARPU and revenue--for each top U.S. operator. For a close look at the findings, check out this special FierceWireless feature.