And, just a reminder, we're not talking about radio services like Pandora (a very different category).
So, let's look at the players.
For some reason, I never hit it off with Rhapsody, who is now the grandaddy of this space. Instead, I always considered it to be a three way race between rdio, Spotify, and the now about-to-be-defunct Mog. Other candidates are Microsoft's Zune service and Sony's Music Unlimited.
But when looking at the features, usability, and the variety of devices on which the service runs, it pretty much comes down to rdio, Spotify, and Google. Unfortunately rdio's fantastic interface is nullified by their truly subpar sound quality. Their attempt at double-speaking their way around this issue on the user forum isn't helping them either.
I had taken a quick look at Google's music service when it first launched. I wasn't to impressed. Like many of their products, it seemed to be "by engineers, for engineers" (though that is not always a bad thing). No, it seemed like their music service suffered from over simplification. It's like they are honoring Steve Jobs' relentless focus on simplicity without giving equal weight to intuitive usability.
That said, I took another look at Google's service this week and I am blown away by how complete an offering it is. No surprise that they have nailed the search function as well as the categorization of music. So far their "I'm feeling lucky" station and their custom radio stations have been on the money. There are apps for iOS now too. Plus it has a music manager which uploads my personal collection of music and mixes it seamlessly with their subscription offerings. This alone is a killer feature No more is my music fractured between what I can stream and what I own. I just type the name and hit play. It is one of those features which makes you wonder why we would put up with it any other way.
So far the music selection seems good too (but, of course, my own tracks fill in some of the gaps).
So what is missing from the service? For one thing, I can't find a way to fine tune the radio stations. Like say I only want to hear songs from a specific artist. It lacks the ability to indicate how far I want to stray from the seed. The only social aspect is through Google+, but that's is probably okay. Finally, the service lacks scrobbling to last.fm. Fortunately there are plugins for the browser and alternate apps on the devices that allow you to send your scrobbles to last.fm.
I am really surprised by the terrific music service that Google has built so quickly. Since they've come this far this fast, I can't wait to see what they do in the next six months.