I had both 64 Emulator 2 and A64 back in the day. Both purchased with adaptors to connect 64 floppy drives.
A64 was definately the better of the two. It had come out later, when 64 Emulator 2 dropped out of development so was a later emulator. It was not too bad but really an unexpanded Amiga of the 500/2000 era had a tough time fully emulating all the 64 hardware so speed wasnt quite there for games and such.
There was also a free 64 emulator (think it was MagiC64 but dont quote me on that its been a long time) that used the hardware from one of those two in order to access 64 drives.