I think the Amiga 500 was a direct response to the Atari ST and the fact that the A1000's limited expandability (compared to the PC XT's slots) (anyone remember the scary zorro 1 add-on case by byte-by-byte)...
The Atari ST originally had a 512 color palette with no BLITTER. The Mega STs added a blitter chip and later the Atari was brought up to 4096 colors at once.. They also had a Dynamic hi-res type mode that let you see all 4096 colors at once.
The thing is they were aimed at different markets. The Amiga was originally aimed at video games and TV style graphics. Atari and Commodore (both at different times headed by Jack Tramiel) were looking to compete against the Macintosh.. Which was aimed at desktop publishing with it's black and white monitor at the time..
Jack Tramiel wanted to make a low cost Mac that everyone could afford that did desktop publishing and music so the ST aka "jackintosh" was born. He tried to get the Amiga away from Commodore but didn't succeed, so he got GEM (with that ugly font) and made an almost clone of the mac desktop. The ST had a monochrome display and when you put a "magic sac" on it with Mac roms could easily emulate a Mac.
They are very different machines. If anyone who knows the amiga "pagestream" lineage, they should know that it original was called "Publishing Partner Professional" and came from the ST platform.
The Amiga didn't have good output or outline fonts till the A3000 and OS2 with outline fonts came around (which was already available thru GEM on Atari making it good for cheap publishing.
The Amiga high res mode was criticized for it's flicker. At the time the ST had a black and white high res monitor aimed at publishing, and color for low end and games.
The amiga could "genlock" and was aimed at video production. Back in those days video wasn't "digital" and required analog video devices..
Seeing the Amiga at the beginning "genlock" with Andy Warhol and Deborah Harry introducing it in New York brought quite a different crowd to the Amiga and set in on a different course to desktop video that was realized with the Toaster.
The ST grew to Amiga like capabilities and they added a multi-tasking version of gem finally. If you compare the ST's OS to Windows 3.1 the ST shines really brightly. It's amazing that GEM didn't beat on Windows on the PC..
They are both unique and it's like comparing apples to oranges. I don't see having a built in midi port helped the ST midi software, with Dr t's being on both platforms and you could plug an internal midi port into your A2000.. Also there is nothing like bars and pipes on the ST..
It's really cool on Windows XP, I can run both OSes on the same machine and the old software through emulators (and several other platforms like 68K Mac and Apple ][GS)
It's like the best of all worlds nowadays with more graphics and sound than all of them ever had before..
-Don