Satellite radio is great in your car and in your home, but it's even better in your pocket. Think of it: Sports scores, stock tickers, and commercial-free music that you can take anywhere.

Transistor radios ushered in the portable music era a half century ago, but satellite radio has a few tethers that have kept it bound to one place and are just now being broken. The first is the need for an antenna to pick up the signal. In-dash satellite radio receivers like the Delphi RoadyXT and Sirius Sportster come with easily-installed antennae, as do home-docking solutions. Portable satellite radio receivers have to rely on internal antennae (assuming you don't want to wear a tinfoil helmet), which can greatly reduce reception indoors. We've also found the urban reception tends to be hit-or-miss.

The other issue is battery life. It takes a lot more juice to power a satellite radio receiver than to power an iPod that just plays music. Don't expect more than 5 hours of playback from these devices.

Because of the need for an antenna and lots of power, portable satellite radio receivers can't compete on size with MP3 players—they're barely pocketable at all. If you're looking for a slim device to slip in your pocket, devices like the Sirius S50 or the forthcoming Samsung neXus might work. Bear in mind, though, that these players only play prerecorded content unless they're in their docks—they're not actual portable receivers.

If you've got big enough pockets, though—and we mean that literally—the XM2go receivers from Tao, Pioneer, and Delphi will serve you well. Interestingly, they're all the same on the inside—the only differentiator is the shape and controls. Even the price is the same.

They also share the same feature set, which includes a feature called TuneSelect to let you know when your favorite tracks or artists are on the air. Each player has enough on-board storage to record up to 5 hours of content, which is handy for those situations where you don't get stellar reception. And all of the players come bundled with more accessories than you'll know what to do with.

In this roundup:

Delphi MyFi XM2GoDelphi MyFi XM2go
The original XM2go receiver sports sexy curves and a slightly chunkier body than the other XM2go products.

Tao XM2go
We think the stylish black Tao XM2go receiver is the best looking of the bunch.

Pioneer AirWare XM Satellite Radio Receiver
The silver Pioneer AirWare looks good, but we had to knock it a bit for design flaws.