Well, let’s make a new thread so others can find it…
I use the R24 on Linux (Fedora), with Ardour in ALSA mode. They play nice together. All 8 inputs can be used simultaneuously for recording. As control surface (Mackie protocol), you get the sliders (8 + master), transport controls, 5 programmable function keys, and mute/record/solo buttons and leds.
I am very happy with the R24 but should it break down I will probably buy an R16. In practice I seldom use more than 8 tracks to mix while recording and I do not use the sequencer, editor and drum kit features. I record with “Always new” so I always get a new file for a new recording. After recording I can play the file, and if I want to hear it during further recordings I assign it to another track. So basically I use bank 1 for recording, bank 2 for recordings to hear while making new recordings. Overdubs are just stored on the SD card. Finally I transport everything to Ardour and the real fun starts.
You can download full documentation from the net.