DRMs haven’t worked, and may never work
Which MS DRM? The Zune Marketplace one, or the ironically-named PlaysForSure one, which are incompatible? And as a resident "Macintard", I have to add that it shouldn't be Fairplay either, and you can bet that Apple wouldn't bother even if Symbian begged. Remember the ROKR? Neither can I. I have to agree that, in terms of DRM you can actually license, MSFT's the only real player. But it's like saying that in terms of hands to cut off, cutting off the left hand is better. The best answer is "none of the above."
Want in on a secret? DRM was never a key to iPod lock-in, because it never works. It was only there to appease the pigopolists. Because the real lock-in, the one that actually works, is user interface. They never even competed with the likes of Sony or PlaysForSure; their competition was bittorrent, kazaa, and gnutella - Offer a slight premium ($1 vs free) for added value (Time saved not downloading mislabeled tracks). That's why they put that big "burn CD/Defeat the DRM" button right in front. Lock in with a comfortable ripper/burner/mp3 player, and since iTunes works so well with iPods...
Anyways, my money is on that this is not for full-out music in as much as the much-more-highway-robbery ring tones.