I chanced it that this 4-port PS2 to USB adapter would work on my G5, with Leopard and emulators, like MAME OS X, snes9x, sixtyforce, Nestopia, and Genesis Plus, despite the website and packaging mentioning nothing about Mac support. I didn't need USB Overdrive, Gamepad Companion, or Controllermate. I am using Emulator Enhancer with these emulators and everything works perfectly! I can map the PS2 joysticks for smooth use in sixtyforce, as the N64 sick and C-buttons work. The only problem I've had at all after much use, is that sixtyforce does not recognize more than the first controller. I think it's an oversight on the otherwise awesome dev's part. I had the same issue with my Mayflash 2-port N64 adapter. I assume I could map the buttons of the second controller to the keyboard controls and set kb to player 2, but that's a hassle. Other than the limitations of sixtyforce and Mupen64(which has no controller mapping), I must post here to verify/recommend Mayflash adapters for Macs. PS: While I was testing N64 emulators with my controller, I found that my G5 is too slow to play Goldeneye! I didn't try any other N64 ROMS, as I fear futility. Emulators for games, like PC Emus of yore, are CPU hogs on slower machines like mine. No probs with any pre-64 emus, though, at all. Even on my G3 notebook, those all run smooth.