I had researched XM Satellite Radio and its competitor, Sirius, for months before choosing a service. At the end of December 2002, I purchased the Delphi SKYFi XM radio with both the home and car kits. I've been using the radio and service for 6 months.
Convinced by the streaming audio previews on the website, I bought into the hype: For $10 a month, you get 100 channels spanning a huge variety of music and talk genres, most without commercials. The service is available anywhere in the continental US by satellite. It's targeted at cars, but can be used in a house if you put the antenna in a window.
The stations have excellent variety. Visit the website for a full list of channels with previews for some. I focus mainly on new and classic rock, so the biggest attractions to me were the channels in the 40s. The rock selection is excellent. Classic rock has more stations than modern rock, but the stations themselves are of equal quality. Deep Tracks (40) and Ethel XL (47) are the two most exceptional rock stations for my taste.
Unsigned bands also have a dedicated channel (52). The reason they are unsigned presents itself directly for many of the bands, but some of them show promise. The biggest advantage of the Unsigned channel is that I can count on not knowing the song they're playing. If I want exposure to new music, it's a reliable source.
The selection of rock music is vast, but would not alone justify subscription to XM. The service's true appeal is the unique variety of content that simply isn't available in significant quantites on broadcast radio. For example, the service has dedicated stations for experimental Phish-like rock, soul, jazz, blues, Frank Sinatra, and each individual decade from the 40s through the 90s. Talk stations are also in great abundance, from old-time radio dramas to modern news, including the syndicated BBC World Service and Fox News. The comedy stations are primarily stand-up recordings, but one station exclusively plays recorded morning shows all day from radio stations around the country.
Some content I'd like is not available on XM, such as National Public Radio (NPR) and the Howard Stern show. Fortunately, most of my desires have been satisfied. NPR is available on Sirius, but it wasn't enough to convince me.
Sirius advertises that it's the only service to be 100% commercial-free, so their higher price is justifed ($13/month). But I haven't come across a single music station on XM that had commercials - the only commercials I've heard have been on the syndicated stations, such as CNET Radio, that run commercials as part of their broadcast. Now that I'm on the topic, CNET Radio spends much of its time playing reruns of David Lawrence's Online Tonight show, a mediocre radio show that has a large percentage of commercial time and a host who doesn't realize that dead air on the radio is bad, and talk radio shows require content preparation beforehand.
The sound quality on XM is decent. It is digital, but compressed heavily with AAC+ encoding, so don't expect CD quality. The music stations sound similar to a 128 Kbps MP3: the highest and lowest frequencies are muffled somewhat, but the quality is not distracting in most circumstances (especially in the car). Talk stations seem to have about half of the bandwidth as the music stations, so they sound noticeably worse, but you aren't likely to notice until they play logo music - the quality during normal speech is perfectly acceptable.
The receiver needs to "see" the southern sky, so if you're stuck under a bridge in traffic or parked in front of a very tall building, you'll probably lose the signal. Since the receiver buffers a few seconds' worth of sound, passing under bridges and other obstacles at moderate speeds does not result in any service interruption. I have fairly good success with the reception at home simply by placing the antenna on the windowsill and tilting it outward. This brings me to my main reason for purchasing XM instead of Sirius - at the time I purchased it, there was no way to receive Sirius' service outside of a car. I go to college in the middle of nowhere where we're lucky if we can get clear reception on anything, even if it's just Jesus stations, so it's very important to be able to listen to the satellite service all the time - not just in the car. Sirius options were also considerably more expensive. At the time of writing this, the price gap has narrowed, but Sirius still does not offer a non-car unit.
The Delphi SKYFi XM unit that I purchased is the second generation of "portable" XM receivers capable of being used in multiple docking cradles (with a non-car cradle available). The first was a Sony unit, but it had a noisy fan and cost $300 with one cradle. The second-generation XM chipset produced much less heat, so fanless models trickled into the market. Customers were unimpressed until the December arrival of the Delphi SKYFi, a smaller, more stylish, quieter (fanless), and cheaper portable XM radio than its Sony predecessor. At $190 with one cradle, and a $50 coupon deal with Best Buy, it was a very convincing offer - one that made it difficult to find any stores that weren't sold out. I ended up driving to three different Best Buys to get one of everything - the radio and the home and car cradles.
The SKYFi is a very nice radio. The interface is very well-designed (I'm an interface nut) with car use in mind. The screen is large and clearly visible, even in bright sunlight and through polarized sunglasses. Two banks of 10 presets are available, or you can simply key in the channel numbers directly, but it's hard to find a reason not to use the excellent jog wheel to navigate the stations. Simply turn the wheel and watch the list of station titles and numbers scroll in either direction, and push the button in the middle of the wheel (or simply stop scrolling for a few seconds) to select the station. Menu navigation also uses the wheel and button, and is just as easy. The information displayed on screen includes the category name, reception meter, station name, station number, and song artist and title (up to 16 characters each by an XM limitation, not a radio limitation). The 5-line display on the SKYFi completely blows away most other XM receivers and head units that typically have 1-2 lines of text at most.
The "Memory" feature is surprisingly useful - if you hear a song you like and want to acquire it later, push Memory and the radio will save the title and artist for you to go through at your leisure. Ten can be stored, and then they are simply overwritten with a first-in-first-out order.
The back of the radio gets hot after about a half hour of use, but I'll forgive it because it doesn't have a cooling fan or external heatsink. It's never been too hot to touch, so I'm not worried.
The radio feels very solidly built and fits easily into most coats, cargo-shorts pockets, and girlfriends' purses. I'm extremely satisfied with it.