In theory Minimig might be more compatible because it's the only one with a real 68k but I don't know in practice. I think there are a few people who have Minimig and FPGA arcade or Chameleon so hopefully they can give you a real world comparison.
original minimig with 68K is probably more compatible than the real thing.
by that I mean you can't easily switch between 1.x, 2.x, 3.x ROM, change ram configuration, OCS, ECS on the real thing.
I can't speak for the other devices.
