Yes, it is faster and the colours seems good. Monkey Island II is really beautiful (most than the Amiga version) It's like the PC version (I don't know how much colors it has, I would say 16 colors for the Amiga version 32 for the PC version).
Did you notice that there is a game that won't show the menu.
Some text are still not displaying (like in the old version).
Full Throttle (even if it would be too slow on the A600) refuse to start, scummvm return to workbench (tested 3 times)
The same game is working on the last AGA version on my 1260.
Full Throttle on ScummVM AGA miss/jump some voices while the voices are playing on the OSX 1.3 version.
That's my little report.