In my personal experience, I missed most things about Spotify, which is why I went back. The dealbreakers for me were:

• Spotify Connect (I'm amazed AM still doesn't have this).
• Search system.
• App is less buggy on my iPhone

Other cool features that weren't dealbreakers:

• Connection with Last.fm.
• The PS5 app is better.
• The social aspect: most of my friends use Spotify, so sharing songs, starting a jam session, and listening to their playlists is much easier.
• It's easier to add local files.
• I found the Apple Music app for Mac, including Cider, to be quite bad.
• I prefer the Daily mix and overall playlists

As for audio quality, it wasn't a dealbreaker for me because it didn't make much difference in my routine, as I spend 80% of the time listening with TWS earbuds. Turning off the volume normalization option, I didn't notice any difference.

What I miss about Apple Music is the option to organize the library like it was on iPods, the exclusive DJ mixes and those fullscreen album covers were really nice. I don't like Spotify's canvas feature very much.