How do U.S. operators rank against carriers from around the globe? While comparing subscriber numbers is relatively straightforward, analyst firm Portio Research took its research a step further by evaluating the world's top operators via a wide range of financial and operational metrics. The result is a much clearer view into which operators are succeeding in the market--rather than which are simply gaining the largest number of subscribers. Which carriers lead the pack in total revenue, revenue growth or monthly ARPU? Slideshow