Apple Music, and particularly iTunes Match, are the opposite of "just works". I wanted to switch back from Spotify, but I found that Match had made a complete mess of my library. Half of my album art gone. Albums were striped with some tracks that were replaced with the iTunes store versions, and some left as my uploaded MP3 V0 versions (most obvious because, even with Sound Check on, the volume levels between each track differ greatly post-iTunes Match).
I've been able to look past a lot of the decline in Apple's software quality, but the data corruption problems springing up (Catalina Mail, iOS 13 Photos incidents also come to mind) are a bridge too far. The primary reason I avoid turning on a new Apple cloud service is that it's likely it'll do something highly undesirable to my data.
Are you referring to the standalone $25/year iTunes Match subscription?
As an alternate data point, I've subscribed to that service for years now (no Apple Music streaming) and have not had any major problems. Lots of custom music tracks as well, which Match has always respected and synced properly across my iDevices.
The only problem I had when first signing up years back was that one of my songs was replaced with the wrong song--but that bad match has since been fixed.
Odd trick: if you have HQ MP3s, and you want them to get “matched” instead of “uploaded”, transcode them to iTunes Plus (256kpbs constrained-VBR max quality AAC) format. iTunes will then be far more likely to get a fingerprint match, for some reason.
Yeah. I cleaned up my library recently. I think I had about four copies in various directories and wanted to get back to a single carnival copy. Whether for Match or other reasons a decent chunk of ripped music was missing. Not enough to just chuck the whole thing and restart from scratch. But enough to waste a day or so of my time.
I've been able to look past a lot of the decline in Apple's software quality, but the data corruption problems springing up (Catalina Mail, iOS 13 Photos incidents also come to mind) are a bridge too far. The primary reason I avoid turning on a new Apple cloud service is that it's likely it'll do something highly undesirable to my data.