I did Xbox Music. $9.99/month for unlimited streaming. Works on PC, Mac (using the browser), web browser (
http://music.xbox.com) Windows Phone, Xbox 360, Xbox One, Android, and iOS.
Presumably you could even use it on a PS3 and PS4 through a web browser, though I haven't tried it.
Functionality? Syncs your playlists, has a 'radio' feature, any music you add to your collection on your mobile device can be automatically downloaded to your PC, any downloaded music on your PC (MP3s, etc.) will be indexed and synced with your 'cloud collection'. I have just around 36 GB of music. If I want to listen to something I downloaded at home, Xbox Music already knows about it and shows it in my collection on my phone. If you use it on the Xbox console, it'll play music videos for songs when/where available.
I also have a Grooveshark membership that I bought way back when for only $3/month before the price went up, but I don't use it much.
On the subject of quality, the **only** time I've heard a difference when talking about CD audio vs DVD audio is when The Eagles released "Hell Freezes Over" in DTS 5.1, and there's an obvious explanation for that... it's using all five channels. When it comes to two-channel audio, high-bitrate MP3 vs FLAC is indistinguishable if the human ear is your measuring instrument of choice.