I love the iTunes Music Store. When Apple CEO Steve Jobs unveiled the shop in the spring of 2003, I called it revolutionary, and who can argue that it's been anything but?

Still, iTunes has always seemed like a stopgap measure, something to tolerate until the music industry got its act together. I think of it, now, as a place to buy music that I like, but not a place to get music I love. If you love something you want a permanent copy, and music from iTunes is fundamentally ephemeral: Nearly everything you purchase from the store will never work on any device not made by Apple.

This week, Amazon launched a beta version of a music store that breaks this lock-in. All of Amazon's tracks are sold as unrestricted MP3s, free of Digital Rights Management, or DRM -- they will work on just about any music player in the world, including an iPod. The store marks iTunes' first real competition. In fact, I think it kicks iTunes' buttons.

First a quick comparison:

• Song quality: Amazon's store sells MP3 tracks encoded at a 256 kbps variable bit rate, while most songs on iTunes are encoded as AAC files with a bit rate of 128 kbps. Audiophiles can argue forever on the merits of higher-bit MP3s versus lower-bit AACs, but in listening to the same song purchased from each store -- Amy Winehouse's "Rehab" -- I couldn't tell a difference.
• Price: Most tracks on iTunes go for 99 cents, while full albums sell for $9.99. Amazon typically beats these prices -- most of its tracks are priced at $0.89, and albums are $8.99. And there are some really great deals: "Mellon Collie and the Infinite Sadness," Smashing Pumpkins' 1995 double album, is just $8.99, DRM-free, on Amazon. On iTunes it's $19.99.
• Ease of use: iTunes is popular mainly because it's drop-dead simple. You buy a song with one click, and because it's integrated into your music player, you never have to fiddle with files on your hard drive to get the songs into your iPod. Amazon matches this performance. The store is on the Web, but after you download a small companion program -- works on Windows and Mac -- you can reproduce the same one-click experience you've come to love in Apple's store (the app automatically adds purchased files to iTunes or another favorite music player). Amazon's store also lets you search for and preview music just as easily as in iTunes.
• Selection: With 6 million songs, iTunes is the clear winner; it has music from all major labels as well as a king's bounty of indies. Amazon has only 2 million tracks, with music provided by just two major labels -- EMI and Universal. Obviously, then, there are a lot of songs you'll find on iTunes that you won't find on Amazon. Of the top five songs on iTunes, two tracks -- the No. 1 song, Atlanta rapper Soulja Boy Tell 'Em's "Crank That," and "How Far We've Come" by Matchbox Twenty, which is No. 4 -- aren't on Amazon. But Amazon does seem to have a lot of top hits, and it even has some artists that iTunes doesn't have. For instance, you can buy each of Radiohead's albums on Amazon for just $8.99; not one is on iTunes.