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Get Unlimited Music on Your iPhone

James Yang for The Wall Street Journal

Q: I listen to most of my music on my iPhone. Out of all the subscription-based music services out there (Rhapsody, MOG, etc.), which one has the best iOS app?

A: I'm a huge fan of unlimited, on-demand music services. They give you all the benefits of stealing music—minus the guilt and jail time! Whether you buy one album a year or you're the type who's clicking the iTunes download button every Wednesday, it really doesn't make any sense not to supplement your audio intake by signing up with at least one of these guys. Around $10 a month for access to millions of songs that you can either stream or download? I don't think there's a better deal in entertainment.

I'm like you: I do the majority of my music listening on my iPhone, so I spend more time with these things in app form than I do on a web browser. Since we're not always in Wi-Fi range (or have unlimited data plans), the true test of a music subscription app is how well it operates in offline situations, so you can use it as you would a plain ol' iPod. With the exception of Spotify, which is just a few weeks old, I've been living with these music apps for several weeks. Here's how they measure up.

—Kevin Sintumuang

MOG

To get a track or album onto your device with the MOG app, search for it and click download. Simple. One problem: There's no option to easily sync songs and albums you want from the web-based version of MOG to the
iPhone. From a laptop you first have to "Favorite" the album, then go to your "Favorites" folder on the app and then click download for every single item—it can get tedious if you're trying to amass dozens of albums. But that's a minor quibble with what's a smooth-running app with superb music-discovery features. One is called Moggles—snap a picture of a record you want to download and it tries to find it in its catalogue of more than 1.1 million albums. Cool to do with your friend's vinyl collection, but not so much in an independent record store unless you're trying to rub the digital demise in their faces. Also cool: MOG Radio. It's not unlike Pandora—you can create stations around specific artists—except MOG Radio lets you download the songs you really like. (The app gives you the option of choosing the quality of your downloads: 320 kpbs or 64 kbps.) I love browsing the new releases and editor's picks every morning before my subway ride. It's like going on a shopping spree at Tower Records—if Tower Records was still around. Oh, how I miss ye olde brick-and-mortar music store. $10 per month for a Primo subscription, mog.com

Spotify

Spotify is the new, much-ballyhooed music-streaming service from the U.K. There's a free version, but there's also an ad-free premium service that lets you sync playlists from the desktop version to your iPhone for offline listening. You can search for songs and albums to download directly from your phone, too. While Spotify has a large selection of music and the app is snappy, my biggest hang-up is that there's no easy way to browse your collection of offline music by artist or song title—you have to poke through playlists to find things. The simplest way around this flaw is to create playlists for each album or specific artists. Hopefully the company will tweak this soon, because Spotify as a whole has a lot of potential—my favorite feature is the ability to subscribe to user-generated playlists. (There are more than 250 million.) A few simple tweaks to make the app more like what you experience on your laptop could make it a strong contender to replace your iPod. $10 per month for a Premium subscription, spotify.com

Rhapsody

With more than 12 million songs, Rhapsody has one of the largest (if not the largest) collections of on-demand music. It also gives members early access to some of the more popular new releases. The app is pretty robust, like a mini version of the browser-based version. You can search by genre, scan new releases and charts and create Pandora-like radio stations. Downloading is similar to MOG: You search for and download songs and albums within the app, but if you want them to magically appear on your iPhone from your laptop, too bad. Albums you want end up in your "Library" folder from which you have to tap download for each one—a chore. What really keeps me from loving this app, though: It's sluggish, you can't download individual tracks and albums are organized alphabetically by title, not by artist. from $10 per month for Premier subscriptions, rhapsody.com

Slacker

Slacker sets itself apart from Pandora, its Internet radio rival, by allowing you to fine-tune your stations with greater control. But the biggest difference is now in the offline space: With Slacker's latest app and premium service plan, up to nine stations can be cached on your iPhone for offline listening. You can also download individual albums, but the steps are a bit cumbersome. That's forgivable because it does one thing better than any other app: introduce you to new music. Nothing beats a well curated station of thousands of songs that you can listen to anywhere—no data connection needed. Slacker is less about downloading every album you ever wanted and more about discovering the songs and artists you never knew you liked. $10 per month for a Premium subscription, slacker.com

RDIO

Everyone seems to be talking about Spotify, but Rdio is my hands-down favorite on-demand music service for one simple reason: The app rocks. It works seamlessly with Rdio's website. Want an album on your iPhone? Just click "sync to mobile" and that's it. No need to dig through the app just to tap download once again. Even entire user-generated playlists can be downloaded with a single tap. (And there are a lot of stellar mixes—Rdio folks are a savvy bunch.) While you can browse new releases and charts, what makes Rdio unique is its social integration. You can see what's in heavy rotation from friends, music labels and magazines that you "follow"—my Rdio music collection makes me seem more on top of yacht rock than I actually am. Bottom line: This is the most well-thought-out on-demand solution for the mobile music listener. $10 per month for an Unlimited subscription, rdio.com

Corrections & Amplifications
With Spotify, songs can be synced to an iPhone as long as the device has an Internet connection. Songs can also be downloaded to an iPhone for offline listening directly within the app. An earlier version of this article incorrectly said the Spotify app had to be connected to a computer via USB or be on the same Wi-Fi network in order to sync music to an iPhone.