[eridius]

You're overthinking it. If you turn off iCloud Music Library, any music you already had on your computer is fine. This means your pre-existing music library will be fine (assuming you didn't delete the music files off of your computer). Yes, there was a bug at one point that could cause it to delete some of your existing music, but it was relatively rare and was fixed shortly after it was discovered.

As for matching, are you adding it from your iPhone, or from your computer? Music matching is a lot more exact if you're adding it from your computer.

[tunesmith]

That bug must be what I remembered - I missed that it got fixed, all I heard was that Apple was working on it. Thanks for letting me know, I think I might nervously shut it off and revert to manually controlling what songs are on my phone. Do you remember any sources on what it was and when/how it got fixed?

I added them from my laptop - I find the matching pretty lousy, though. Bjork recordings are replaced by acoustic remixes, live-radio performances of songs are replaced by studio recordings, etc. And then of course some of my own songs are replaced by weird recordings I've never heard before. It seems that any time I'm out and about and listen to a playlist for 30-45 minutes, at least 1-2 songs are wrong.

All of these recordings are of course still fine on my laptop itself - I know not to delete those.

[eridius]

I don't really know the details on how it was fixed, but I feel like it was fixed within a week of it being first reported.

As for the matching, I'm not sure what to tell you. To the best of my knowledge, all of the music I have was matched correctly (or uploaded if there was no match). That said, I was originally an iTunes Match subscriber, and it's certainly possible that maybe iTunes Match used stricter matching, though I don't know why that would be because that sounds weird.

[astrange]

In the past Match used stricter matching than Apple Music for no real good reason. They are the same now.