Best fightpad for PC?

Insides of the original Neo geo game pad
http://www.gamesx.com/controldata/neopadfix.htm

The Neo Geo PS3 USB pas uses a similar setup for the thumb stick
The key difference is the additional buttons and the USB encoder

The original NEO GEO pad only had a PCB to hold the switches and button contacts into place, other than that there no circuity to speak off
The switches and contacts go directly to the controller cable which plugs directly into the AES and NEO GEO CD consoles or MVS board
some models of the MVS main board has 15 pin d sub connectors for NEO GEO Pads, and its not hard for those main boards that lack the connectors to add them to the existing Jamma harness.

The original NEO GEO game pads and arcade stick is the easiest to convert to modern systems, as there no need to mod the pad or stick it self.
You just need to include a DB 15 connector wired to the appropriate connectors on a modern game system PCB.

NEO GEO game controller cable pin out
http://gamesx.com/wiki/doku.php?id=controls:neo_geo_controller

I could never figure out how to play six button fighters on traditional gamepads, guess I’m just bad.