I had Google Music for 6 months and, while their music selection is great, their UI is horrendous.
For example if I'm scrolling through an artists albums, they would list every release of an album (European release, NA release, Japan release, extended version, radio friendly, non-radio friendly). Maybe that's nice for some? It was just a hassle for me.
Overall navigation through the app I found to be really, really bad.
I've never noticed that myself, but if you say it's a feature, I'll believe you, and applaud Google for doing it that way.
As different album releases often contain different recordings, sometimes finding EXACTLY the song I want to hear is hard to do. Having fallen for Sublime when they were still playing live shows, but knowing that they were only able to capitalize on their fame after the death of their singer, they've (necessarily) released a bunch of versions of old songs, which are often vastly different from one another. Finding JUST the right recording of a particular song is only enabled by having that otherwise needless duplication in the selection process, and I'm certainly willing to endure that if it means being able to add every version of X to my queue to find just the one I was looking for.
Offtopic, if they could only add Whitesnake's "Starkers in Tokyo" recording, I'd have just the right version of "Here I Go Again" in my library.
The downside being that the duplicate detection is nonexistent - I have a playlist I sync to my phone, and often when I'm listening on "I'm Feeling Lucky" mode at my PC a song will come up that I like and I'll add it to the playlist. As you can imagine, this often leads to multiple versions of the same song taking up valuable space. The same goes for thumbs-up and thumbs-down - it won't apply to all versions of a song. Which is fair enough when they're actually different (live, remastered, remixed or whatever) but when we're talking about the European release, NA release and Japan release of the same album it's often literally exactly the same recording.
Trouble is, I can't come up with a "best of both worlds" fix that allows both (perfectly valid) use cases.
MusicBrainz has separate concepts of "works", "recordings" and "releases" that I think should allow for some resolution of your problems. I'm not aware of any tooling that actually makes use of this level of data though -- anyone more familiar than me?
On the other hand, some people don't care about the several slightly different recordings or remixes of "Santeria" and just want to listen to Sublime? A good UI would allow for both rather than just point the firehose of information at the user.
For example if I'm scrolling through an artists albums, they would list every release of an album (European release, NA release, Japan release, extended version, radio friendly, non-radio friendly). Maybe that's nice for some? It was just a hassle for me.
Overall navigation through the app I found to be really, really bad.