It's coming to Android and iOS so it looks like Microsoft are actually pushing this platform properly!
Pricing is slightly cheaper than Spotify's premium service in the UK which nice. The web player needs a few more social features for people who like that sort of thing.
Update: Popped on some decent headphones and gave the service. Sounds good. Clean interface. I actually really like it if I have a specific desire in mind. The explorer section is a bit basic. This is only the web version though so the apps might be a different story. All in all I like what I see so far and the initial unlimited free usage will go down well with a lot of people I don't doubt.