MCC-16 is NOT a software emulator, but a hardware simuator in FPGA, just like the Minimig.
Comparing it with emulation is just plain silly: it behaves EXACTLY as hardware at electronical level. So your post is rushed, orb85750, and it makes no sense at all.
On the other hand, I have and MCC-16 here (as I have a Minimig and an Altera DE1), and it only supports C64 for now. It makes a good job: most games work flawlessly, but some of them need slight adjustments: Tim Follin's excelent work for Ghouls'N Ghosts has a small sound problem with one of the channels, for example, and Creaures 1 & 2 are unplayable due to a bug in the VICII implementation.
Those should be fixed soon, however.
The Amiga core is unreleased. I hope they release it soon! It's based on the Minimig core with an improved 68K core (not TG68K anymore, I believe).
EDIT: My MCC-16 is the VGA version, so no Atari2600 core for now. Not that I matter, the Atari2600 is a piece of crap for my taste.