But I'm glad it's working well for you. For the most part, it's been exceptional for me too, but sometimes it just goes tits up...
Make no mistake, I have my share of complaints about iTunes. I am a bit mystified when people say that it messed with their files (as opposed to messing up its own database). When I look at my music files in Finder, the "last modified" dates are years in the past.
I recently took advantage of the limit increase for iTunes Match - I had iTunes re-import my entire music collection. It correctly ignored all the previously-imported material, added all the new material, and shipped a ton of unmatchable songs up to the cloud (1). After all that, I randomly checked the last-modified dates of my old material and they are from 2005-2006 as I would expect.
I do not use Apple Music, so it is possible there is something going on with that.
A.
(1) Shipping unmatched files up to the cloud was a fiasco. iTunes maxed out my upload capacity to the point where it broke its own connection to the iTunes store. The end result was that it would upload a few files, break, sit around for a long while, then upload some more. I had to install my own rate-limiter to keep iTunes from hurting itself. Otherwise, it would have taken months to upload the unmatched files. (talk about old bugs needing to be fixed!).