This one polls every 5ms, so you have 5ms guaranteed latency, when mine reacts on USB async interrupts. Also it takes a hammer approach and simulates a joystick via VHID+WirtualJoy, whereas mine just maps the USB packets to sets up a HID descriptor and passes it straight to OS X's IOKit. You can't have it be more lightweight and native: connect pipes and tell OSX how to understand packets in the most standard way possible.

Latency matters a lot to me, especially in emulators as it creates a terrible uncanny valley (even more when you have the original hardware to compare to). Using Higan on OpenEmu with this controller, latency is really low and I have the feeling very similar to "native" NES when I play Megaman.

Also once you go in Big Picture mode on Steam and configure the gamepad, mine works like a charm in all games I threw at it.