A new study from J.D. Power and Associates revealed that Sprint Nextel and T-Mobile customers tend to be the most satisfied with their wireless services.

Of the top four wireless carriers in the United States, Sprint and T-Mobile both earned five out of five "Power Circle Ratings." Verizon received four power circles, while AT&T was hit with a meek two-out-of-five ranking.

Sprint customers, the report noted, tended to be satisfied with their carrier's website sales and offerings, as well as service costs. T-Mobile, meanwhile, ranked high in terms of cost of service.

The study also evaluated customer satisfaction among non-contract service carriers. Of those, Boost Mobile ranked highest with a five-out-of-five rating, followed by MetroPCS and Virgin Mobile, each with four power circles.

The American wireless market is poised for a shakeup with the pending acquisition of T-Mobile by AT&T. The merger was announced this March, but the Federal Communications Commission has since put a temporary halt on the deal to review whether it will violate antitrust laws.