Yeah, it'll be a while before VSTs get caught up. I did some testing with MainStage concerts using Apple's built-in stuff and my wife's M1 MacBook Air performed just as well if not better than my $4000 MacBook Pro. This is why I'm so excited for Apple Silicon computers for this sort of work.
MainStage doesn't run on Windows, and it's the software all the shows use. Even shows that use Ableton Live for playback sometimes use MainStage as a frontend software controller hooked up via IAC.
Form factor is most important. After that, price. Then third is probably the cooling situation, though we can install some extra fans if needed. Better I/O doesn't really matter here as we only need 2-3 USB ports, Ethernet, and display.
Thanks. I didn't originally write it as something to be shared, but I guess I should from now on. I definitely have a lot more thoughts about it, so might do a follow up in the future. Regarding union rules, synthesizes are fine but there are some "house minimum" requirements so usually there are 2-3 keyboardists and then other acoustic musicians as well.
Actually RAM is not the issue. Most samplers only load the attack portion of samples into RAM anyway. SSDs are so fast now, we can stream the rest without issue. The problem has always been CPU-related as we have to set a low buffer size to minimize latency. The previous Mac minis we've worked with struggled with some of the more high-CPU plugins (VSTs as well as FX), so we had to compromise in many cases. I did some testing with an M1 MacBook Air, and it blew the old Mac minis away in terms of performance and stability. Very much looking forward to see how the M1 will be used in these live production situations.