(MONEY Magazine) – Catherine Zeta-Jones wants you. So does the creepy Sprint spokesman. And Verizon's "Can you hear me now?" guy too. If you've watched 10 straight minutes of television lately or driven a stretch of billboard-studded highway or even flipped through this magazine, you know that cellular-phone companies are wild for your business. They shout about having the lowest prices or the largest network or the hottest phones (yet never, it seems, all three), and their all-out marketing efforts have become as loud and annoying as a cell phone ringing "I Will Survive" full blast in a movie theater.

While there may be no shutting them up, remember that they're advertising for a reason. Yours is one of more than 170 million active cell phones in the U.S., and the five nationwide carriers want to capture as many monthly payments as they can. While no one thinks cellular minutes will get much cheaper as a result, providers are striving harder than ever to meet customers' needs in different ways. The companies want you to switch—a quarter of all cell-phone users did so last year, and there may be good reason for you to follow suit. Consider this: 40% of all minutes go unused. Clearly we consumers should be shopping for our precious minutes more carefully.

Now's the time. For one thing, cellular carriers really have begun to differentiate themselves (see our table on the facing page). And the system that allows customers to keep their numbers when switching carriers is running smoothly. Plus, recent mergers have changed the rules of the game in ways that may affect your bill (see "All Together Now").

And there are other differences that have nothing to do with price. "If marketing plans are all the same, service-related issues help determine customer satisfaction and loyalty," says Kirk Parsons, senior director of wireless services at J.D. Power & Associates, which surveys cell-phone users on customer satisfaction and call quality. "It's about the blocking and tackling." There are two kinds of service, you see: that measured by the number of bars on your phone's screen at any given time, and that gauged by the helpfulness of the person on the other end of the customer help line. So think of your carrier as something you shop for selectively rather than as a utility that's foisted upon you. Be demanding. Hold companies to what they say in the ads. Keep reading to find out how.

Nationwide carriers express their individuality