I can't say what is the better emulator, i don't use a C64 emulator on my Amiga since years, but forget to use on a plain A1200, i remember that existing emulators some years ago didn't work at full speed on my A1200 with a Blizzard 030 / 50 Mhz. And about d64 images, i think that some emulator works with d64 images. Try to search on aminet on misc/emu, exist different emulators of C64.
