NEW YORK (MONEY Magazine) - Nothing makes a long car ride longer than losing your radio signal in the fourth quarter of a tied ball game.

And when the oldies station is cranking out hit after golden hit on a Saturday night, nothing sucks the life out of the party like 17 minutes of commercials. Even if you tune in and hear a great new song Monday morning, you can bet you'll be sick of it after you've heard it 37 times -- and it isn't even lunch yet.

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The cost Sirius and XM are like Coke and Pepsi in the 1980s -- locked in a high-stakes battle to the death. Their pricing plans aren't that different, since neither company wants the other to gain an advantage. Here's how it breaks down. Subscriptions  Sirius  XM  Monthly  $12.95  $12.95  One year  $142.45  $142.45  Two years  $271.95  $271.95  Long term  $499.99 (for life of radio)  $599.40 (for five years)  Monthly fee for additional radios  $6.99  $6.99

Sports line-up Neither XM nor Sirius carries every major sport. Sirius  XM  National Football League  Major League Baseball  National Basketball Association  NASCAR Racing  NCAA Basketball Tournament  PGA Tour

FM radio has its fair share of problems, which is why, if you want to hear some music, you probably pop a CD into your 10-disc changer or scroll through the reams of songs on your MP3 player.

The problem is, those are all songs you already have. If you're interested in something new to listen to, you're out of luck.

But as you've no doubt heard, two competing satellite-radio companies, Sirius and XM, want to put a different idea in your ear. By subscribing to one of these services, you get radio with no commercials to interrupt the music. You get talk, sports and entertainment programming you can't hear anywhere else (such as Howard Stern, who famously decamped to Sirius last month). And you get a signal that comes through crystal clear from coast to coast.

In order to receive a signal, you have to buy a radio for $30 to $300, pay the monthly subscription fee and then tune in to one of either network's scores of channels. Both companies think this is worth $12.95 a month. And after a thorough review of the programming offered by the two providers -- on a total of almost 300 stations between them -- I agree.

Satellite radio is the best thing to hit the airwaves since the fireside chat. What's on XM and Sirius beats the pants off FM radio and, yes, your CD collection too. Getting both services would be cumbersome and expensive, since each works with its own set of equipment. The companies are trying to match each other in an escalating arms race of content, but there are subtle differences. To find out which one sounds right for you, read on.

XM and Sirius have similar channel lineups: Each offers a '60s station, a '70s station, three different jazz stations, three classical stations and about 60 others.

The real treats are the stations that spin deep cuts, not just the hits. But even the mainstream stations go further than their terrestrial counterparts.

Sirius' artist-specific stations earn extra points: Even the most hard-core Springsteen, Elvis and Stones fans will hear rarities, alternate versions and full-length, live concerts obtained through exclusive deals.

XM is countering with new shows such as Bob Dylan's weekly spot, which should start up in the coming weeks.

Satellite radio is a fan's dream. For one thing, you can usually tune in to your team's home broadcast from anywhere in the country -- if you're a New York Giants fan but you live in Boise, you can still hear the local New York call. What's more, the broadcast will never turn to static, no matter how far you drive.

Neither XM nor Sirius carries every major sport, but both are tackling the college sports market with vigor. Sirius makes deals with individual schools (more than 125 top athletic programs), while XM partners with entire conferences to carry more than 100 schools.

Sirius and XM are at war: Both are courting big-name personalities in the talk and entertainment arena. So, as with sports, neither service has everyone. Sirius, though, has been shelling out more of the big bucks lately and is the clear winner when it comes to top-tier talent.

Sirius, as you may have heard, has Howard Stern. There will be daily broadcasts, replays and new shows hosted by Stern's cohorts. They also have Martha Stewart, with round-the-clock advice on living the perfect life. Live call-in shows will be on -- sometimes with Martha herself -- on gardening, cooking, entertaining, kids, stenciling -- all the hits. Their NPR lineup includes shows from local NPR affiliates, including "Car Talk" and "Fresh Air" -- but no "Morning Edition" or "All Things Considered."

XM has the BBC World Service, a live feed of the 24-hour English-language global news broadcast out of the U.K. They also have Air America, with political opinion from Al Franken, Janeane Garofalo, Jerry Springer and others. (Both services have other right and left political channels.) In addition, XM Public Radio shows include "This American Life," "Studio 360," Leonard Lopate and former NPR personality Bob Edwards.

Satellite radios have a digital screen that allows you to scroll through the complete channel lineup and see what's on, and both services advertise programming between stations (for example, the deejay on the '60s station might plug a basketball game that's on that night).

But a display screen is only so big. To inform their customers of what's on, Sirius and XM both rely heavily on their web sites to advertise regular programming, special broadcasts, sports schedules and live concerts and interviews. They are also where you can go to listen to your subscription while at work -- subscribers get access to an audio feed that can play over the Internet.

Web winner: The Sirius site is easier to navigate and is also far more informative than XM's -- or at least makes it easier to find and read the programming information you want. For one thing, XM's site is more of a hard sell. It's cluttered with come-ons like "Radio to the power of X" and "Listen Large."

To listen online through your computer, XM is free with subscription and $7.99 for an online-only subscription. Sirius service is free with subscription, but has no online-only subscriptions. That's for music and Sirius-produced content only.

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Can Stern make satellite radio hum? Click here for more.