I recently cancelled my Google Music (trial) subscription because it's frustrating to use and so damn ugly.
I'd love to be able to sort by date, see what I've recently listened to and scrobble to last.fm but I don't seem able to do much.
Feature-wise it's pretty much the same as all the alternatives on the market with the marked exception of being able to bring your own music. That said, it's like it's been built with no real idea or goals as to how or why it might be used.
The main screen isn't especially useful. In my case it lists “recently added” music, which might be useful if I hadn't recently added my entire music library. I've been using it for almost a month now and it's still frustrating trying to find music I'm interested in listening to.
The whole "radio" concept is annoying too, I just want to listen to an album but it's difficult to do that if the album isn't in my library. For a search company, the search workflow is just rubbish.
Then there's the “loading” dialog every time you open the web app. Just cache, damn it! And that orange? It's just all-around a bad user experience.
I'm heading back to Rdio for my on-demand streaming since they seem to have their search sorted at least. I do hope Google Music gets better but I'm not going to put up with it while there are better alternatives around.