I also signed up for iTunes Match, which provides the only part of Apple Music I care about (while also costing way less). And it seems to be doing a good job of pre-populating my device with music, and Smart Shuffle is able to play from iCloud while I’m on wifi and then automatically switch to stuff that’s locally cached when I’m not on it, so hopefully that makes for a reasonably seamless experience.
I guess with the vast quantity of music I have at this point I don’t really care about play stats for excluding stuff I’ve heard recently since I have so much of it that it’s less likely for duplication to happen like that.
The iPhone does have a setting for how much music to prefetch but as far as I can tell there’s no way to tell it which playlists/songs/whatever to prioritize; as far as I can tell it intends to focus on stuff that I listen to already, which is pretty much the opposite of what I want.
I suppose that if I care incredibly deeply about having proper randomness available on my phone I could just get a 512GB iPhone when I inevitably upgrade. I guess that’s a decision I can make next time I’m in Portland (which is in just two weeks).
One annoyance with iTunes Match so far is that it refuses to cloud-upload songs which it sees as duplicates. Fortunately its duplicate detection seems to be a lot better than in the bad old days of just matching artist and title, but unfortunately it still means that if you have an artist who has released multiple close-enough-to-each-other versions of the same song on different albums, or has released a best-of compilation, you’ll only get one rendition of it and it won’t appear in all the albums, and you can’t even choose which one is the canonical album placement. Kind of annoying. But less annoying than all the other things iTunes annoys me with, I guess.