I think that Go64 was so early that it was not a very good emulator by today's standards - i.e. it probably couldn't run much of what you throw at it, other than BASIC programs.
However, that hardware device that comes with it looks like it might be useful for attaching a 1541 drive to a real Amiga (like an X1541 cable). So it might be good at least for transferring programs to the Amiga.
The good C64 emulators for the Amiga were Magic64 and FRODO. Magic64 ran well on my 68040 A2000 as long as I set it to do some frameskipping. FRODO was the most accurate emulator, but was too slow on my 68040.
