From the Zunerama blog:
How does Marketplace stand up against iTunes Store, in the world of Rock'n'Roll..?
Very well, it turns out.
Despite the prevalent notion in the blogosphere that Marketplace music content pales in comparison to Apple's long-established iTunes Store, my own experience is that I've rarely come up short when searching for music in Marketplace. I decided to test this for the Rock'n'Roll genre.
So I recruited some volunteers from Zunerama's forums and, using Rolling Stone Magazine's 500 Greatest Songs of All Time, we researched and recorded the availability of every one of them, in Zune Marketplace and in iTunes Store.
For each song, we checked whether or not the song appeared in the store's catalog, and confirmed whether or not the song was available for download.
To be consistent, we set some rules for what counted as an "available song":
1. Some songs are not available in either store for individual purchase, but can be purchased as part of an album; we give those songs full credit as being available.
2. In a couple of cases, we found that songs are available only in live versions and not the original studio release; we give those songs full credit.
3. To get credit, the song must be available with the specific artist named in the Rolling Stone list; covers of the same material by other artists or tribute bands don't count.
4. In cases where the original album was not available, we still give credit if the song is available in a compilation album - as long as the compilation album has that particular artist performing that particular song. So, an appearance in a "Best of" album would count, even if the original album was not available.
We treated iTunes Store and Marketplace consistently when these anomalies came up.And the results: out of Rock'n'Roll's 500 greatest songs, Marketplace has 458 songs available for download. iTunes Store has 453 songs available for download. Surprise! A slight edge to Marketplace.
But stay tuned!! These figures will change over time, as both iTunes Store and Marketplace expand their content. Indeed, if rumors prove true, in a few days iTunes Store's results in our study could surge by no less than 23 songs, if they actually make all Beatles songs available through ITunes Store. That would be a nice coup for Apple, and one - as a Beatles fan - that I would applaud.
Thanks to our Zunerama members for their help with the research: supernova, Hollikins1101, glowbee, blazingwolf, Sw0rdf1sh, tmgux, rshives, inflamesfan018, ryango119, and stryker