Xbox Music Pass -- If you prefer to have an all-you-can eat music option that streams songs to your computer or portable device then this is what you'll probably want to go for.
Free Account: Microsoft offer a free account so you can try out their streaming service without having to financially dive straight in and pay a subscription free up-front. As with other services that sport a free account, the songs that you listen to will come with advertisements. At the time of writing, there's unlimited listening for the first 6 months on a PC or tablet running Windows 8, but after that it will be limited to 10 hours per month unless you upgrade to the paid-for subscription tier.
Paid-for Subscription: paying a monthly fee for a full Xbox Music Pass has several benefits which include: unlimited listening on any device (not just PC / Tablet as for the free account); songs are free from advertisements; you can sync to any of your compatible devices, and if you've got an Xbox 360 you will also gain access to thousands of music videos to view on your console. To be able to sign up and use an Xbox Music Pass (free account or paid-for), you will need either: Windows 8, Windows RT (PC or Tablet)), Windows Phone 8, or an Xbox 360 console.
- Xbox Music Store -- If you're not a large consumer of music and don't need an almost unlimited supply, then you may prefer the more traditional way of owning music by purchasing and downloading it. The Xbox Music Store has a large music library where you can either buy individual tracks or entire albums (just like the iTunes Store for example). The music comes in the MP3 format so you can play it back on almost any device that supports MP3 audio files. To access this part of the Xbox Music service you will need either: Windows 8, Windows RT (PC or tablet), or Windows Phone 8.
- Music Library Size -- according to Microsoft, their global catalog currently has 30 million tracks in it. This doesn't mean to say you'll be able to access the entire catalog as it all depends where in the world you live. For example, if you live in the United States you will be able to stream approximately 18 million tracks from the total global catalog.
- Smart DJ -- as the name would suggest, Smart DJ is a compilation tool for creating your own customized radio stations or playlists. It's similar in fact to other personalized Internet radio services like Pandora where you can discover new music by typing in the name of an artist to see which other artists have a similar musical style.
- Offline Mode -- for times when you need to listen to songs without an Internet connection, Xbox Music Pass subscribers get the benefit of an offline mode. This is also useful for times when you just want to conserve your broadband data usage (streaming can use quite a lot) -- or making sure your portable device's battery power is maximized. Instead of streaming, the songs or albums you choose will be downloaded to your device's storage space.