I came back pleasantly surprised with the current state of things. Minus the underlying linux sound system, which is still a mess of things that barely work together. (I have a lot of expensive/pro plugins and all the DAWs on the Mac, so this was mostly a filtering exercise - what I can use on Linux that can still mix/master a whole project).
- I'm not a FOSS purist in audio, so that wasn't a requirement. But I am 'linux purist' so no VST wrappers of windows DLLs etc.
- Watershed moment for me: Toneboosters and Kazrog coming to Linux. Along with u-he, these make for a very, very high quality offering. You can easily mix a commercial release just with these. Kazrog isn't even 'Linux beta' like the rest, proper full release on Linux. I was briefly involved in beta testing for Linux, Shane & co are incredible people.
- I have most/all DAWs for the Mac. Reaper and Bitwig on Linux are enough for me and feel like good citizens in Linux. (ProTools is never coming, neither is Logic. But addition of Studio One makes for a really good trio).
- Any USB class-compliant audio interface will work (modulo control applications which generally aren't available on Linux, so ymmv).
- iLok is missing, which removes a whole host of possible options (I have 500+ licences on my iLok dongle, none of that stuff is accessible). I can't say I miss iLok, but I do miss Softube (not that it's available on Linux, iLok or not).
I made a few 100+ tracks mixes on my thinkpad with Reaper and the above combo of plugins, it worked just fine.
But Linux is still Linux, and 30 years later still annoys me with typical 'linux problems', which generally boil down to 'lack of care'. UI is still laggy, compositors be damned. While Reaper is butter-smooth on a Mac, audio thread never interferes with UI (and vice versa), it can get quite choppy on Linux. If you allow your laptop to go to sleep with a DAW open, chances are good that upon resuming you'll have to restart it as it will lose sound. And a lot of smaller annoyances that are just lack of polish and/or persistent bugs, that I'm sadly used to on Linux (want to switch users on Linux Mint? The lock screen can get hella confused and require a lot of tinkering to get the desktop back). But overall, it's a million miles away from a hobbyist endeavour that Linux audio used to be until recently. I could get actual work done with Linux this time around.