While it's true the Amiga never got the breadth of serious music sequencing software that was on the ST, I never experienced any issues with MIDI jitter or timing.
While the Amiga could do multi-tasking, applications could also optionally take over the entire machine, which many games obviously did but so did real-time video applications like the Video Toaster, animation, audio and music apps. Lots of Amiga games and video apps "raced the beam" in real-time without ever dropping a field of 60 fps video. So, at least in principle, the Amiga hardware was as capable as the Atari ST in terms of ability to respond to interrupts at MIDI rates. The Amiga also had video editing software, which back then, involved controlling three professional VTRs in real-time over that single serial port to do A/B roll editing on precise timecodes 29.97 times a second.
So, yeah, I agree that the Atari totally won the MIDI production music market because it had much better software applications. If you were primarily a music producer or studio, there was certainly no reason to pay more for an Amiga's custom graphics capabilities - and if you were serious, the Amiga's more limited music app selection made the choice for you. My only quibble is that, IMHO, the claims of 'MIDI jitter' somehow being endemic to the Amiga were more Atari marketing FUD than reality. I don't doubt that some user at some point did something on an Amiga that caused MIDI timing issues, but it wasn't because of some fundamental hardware limit. It was due to configuration, some app incompatibility, bug or some other solvable issue - because similar timing issues could occasionally happen on the ST too - and then would be solved.
While the Amiga could do multi-tasking, applications could also optionally take over the entire machine, which many games obviously did but so did real-time video applications like the Video Toaster, animation, audio and music apps. Lots of Amiga games and video apps "raced the beam" in real-time without ever dropping a field of 60 fps video. So, at least in principle, the Amiga hardware was as capable as the Atari ST in terms of ability to respond to interrupts at MIDI rates. The Amiga also had video editing software, which back then, involved controlling three professional VTRs in real-time over that single serial port to do A/B roll editing on precise timecodes 29.97 times a second.
So, yeah, I agree that the Atari totally won the MIDI production music market because it had much better software applications. If you were primarily a music producer or studio, there was certainly no reason to pay more for an Amiga's custom graphics capabilities - and if you were serious, the Amiga's more limited music app selection made the choice for you. My only quibble is that, IMHO, the claims of 'MIDI jitter' somehow being endemic to the Amiga were more Atari marketing FUD than reality. I don't doubt that some user at some point did something on an Amiga that caused MIDI timing issues, but it wasn't because of some fundamental hardware limit. It was due to configuration, some app incompatibility, bug or some other solvable issue - because similar timing issues could occasionally happen on the ST too - and then would be solved.