Sharp x68000 was nice but technically limiting. It was basically designed to do games like SF2, Ghouls n Ghosts and Gradius specifically.
Oh and Amiga Space Harrier and Outrun should have been pretty much arcade perfect but for some real sloppy conversion work and minimum improvement on Atari source code.
technically limiting?
Not really. The system was clearly superior to the Amiga. They're hard to find, but would make a neat system to port AROS to.