I'm biased because I work for Google and dogfood Play Music, but for me it's a great combination of:
* A free music locker you can upload your songs to
* iTunes-like store, with non-DRM'ed files and offline support
* Spotify-like subscription service, with offline support
* Pandora-like radio stations, with the addition of "I'm Feeling Lucky" radio that adapts to your listening habits, and offline support :)
* Songza curated playlists/stations
* Great web and mobile apps
* YouTube video integration (I don't really use that though)
* Pretty decent discovery
What it lacks is Spotify-like social features: profiles, activity, etc.
I agree with you on this. This is the reason I left Spotify. I pay to conveniently access quality music anytime, anywhere.
The social aspect doesn't make much sense with the plethora of streaming music service options available it seems anyway. We have services like Twitter and Facebook and Reddit for social and we have Google Music, Beats, Rdio, Spotify, and others for Music. My experience is that all my friends are each using their own music service, so unless everyone was using the same one it doesn't seem to make sense for the use case of sharing playlists or new music with friends.
Yet I really want that because I constantly have friends asking for new things to listen to, and want to check out what some other people are into. It's one of the few social features I get a lot of value from.
Social features are the primary thing I miss from rdio.com, but they have explicit "friending", otherwise you'd see nothing. I assume Google would use all their data to show you everything everyone is listening too and provide little control.
Google doesn't get social. I can't even share a photo from Google Photos onto Facebook that shows the actual photo; at best they'll share a link with a small thumbnail – at worst it prompts people to login to see it and shows nothing of value on FB. I get it...they're competitors...but the effort required to share an "Google Awesome" photo drives me away from sharing the good stuff they do do.
Can I listen to what I want when I want? I tried looking for particular artists in Play Music and all I get is "X Artist Radio. This will play songs by blah, blah, blah, X Artist, blah". I just want to listen to X Artist. Why is this so hard?
edit: forgot the store.