Good news, music lovers: Spotify now has a free app and streaming service for Android and iOS. The Swedish music streaming company announced its mobile expansion this week, along with the addition of Led Zeppelin to its song catalogue.

Until now, Spotify's free streaming was only available on desktop computers, and streaming on mobile devices was only available to premium subscribers who paid $9.99 for the privilege, or to nonsubscribers through a short free premium trial. Now the Spotify app will allow users to stream music on their iPhone or Android device, making the company much more competitive with streaming radio services like iTunes Radio and Pandora, which both already allow streaming on smartphones and tablets.

"Today we're giving people the best free music experience in the history of the smartphone and the tablet," said Spotify founder and CEO, Daniel Ek, according to Spotify's release. "Whether you're going to the gym, or having a party with friends. Just sit back and let Spotify serve you great music for every moment of your life."

The announcement was made at a New York City press conference by Ek, who said that the goal of the initiative is to provide greater access to its streaming music service, and pick up more paying premium subscribers in the process. "Our very clear mission is getting more people to access and discover more great music," said Ek, according to BBC News. "Along with more free users there will be more subscribers, and that means more revenue back to the industry."

That statement contains two caveats. First, "more revenue back to the industry" could be taken with a grain of salt, since artists have complained about how little they get paid per stream. However, Spotify has recently been transparent about how much artists get paid, setting up a "Spotify Artists" webpage with analytics for artists to track their royalties, along with releasing figures on how much it pays musicians in general. It should also be noted that artists' complaints about low royalties from digital music services are nothing new, and are not unique to Spotify.

The other caveat, "more free users = more subscribers," affects users directly: Spotify has a free service on mobile devices, but it is not the same thing as the premium service. It's also more limited than the free desktop version of Spotify. Free Spotify mobile streaming is more like other streaming radio services, except it pushes the "upgrade to premium" recommendation hard.

Mobile users can search for artists and albums, or browse through premade playlists, but they can't pick a particular track to listen to. Instead, there's a "Shuffle Play" button, which is basically like the "play radio" button on Spotify's free desktop service. Users have access to millions of songs, but they're all on shuffle, and there are only 6 skips per hour.

In addition, the app is full of disabled, but clickable, premium features. On a first hands-on tour, I couldn't tell which features required the premium subscription and which ones were integrated into the free app.

This is on purpose, and it feels like Spotify is trolling you for a premium signup.

For example, there's a "shuffle" icon in the corner that is always on. Attempting to disable it brings up a "upgrade to run off shuffle mode" pop-up, with a button to "get premium."

Lots of other menu features or in-app actions bring up the same pop-up. It takes a little bit to remember what you can and cannot do on the app, and Spotify doesn't give any contextual clues. Also (of course), there are ads, but seemingly less often than Pandora, surprisingly enough.

Despite the caveats, at least there's a working Spotify app now, and there are some great, useful integrations with the desktop model, like the "starred tracks" feature, which will help you discover new favorites on the go and listen to them again on your computer. Also, when you pick an artist to listen to on shuffle, Spotify will only play that artist - not a couple tracks from that artist mixed in with dozens of tracks of "related music." "We're the first and only service to obtain licensing rights to do this," boasted Ek. For music fans that love diving into a deep discography and want to continue to do that while out of the house, Spotify is now notably better than iTunes and Pandora.

Spotify is still behind Pandora, with only about 24 million active listeners compared to Pandora's 72.4 million. Expanding into 20 new countries, adding Led Zeppelin, and offering a mobile music experience unlike its competitors will undoubtedly help close that gap.