nate1222: For MK1 and MK2, F1 is the "start" button. F10 goes into "options". In options, go to CONTROL1 and press right arrow to switch to "4 BUTTON JOYSTICK". I use a Logitech F310 set to Direct Input (it also has an Xinput feature), and it works pretty good.
There's no "high punch" though; the punch button seems to just be a basic punch with no "high" or "low" to it. Still pulls off special attacks that normally involve high punch just fine though.
For MK3, Enter is the "start" button.
Hmm
Honestly, I really haven't had any issues to speak up with the setup that I'm using. I bought a Retro-bit Sega Saturn USB controller and its worked pretty well overall for MK1 and MK3. ( I haven't tried MK2 recently ).
For MK3, what I'd HIGHLY recommend is if you're using a controller that prodominantly uses a D-Pad, is to skip the joystick calibration step entirely by pressing escape after opening the game for the first time. For me, it ran flawlessly and I was even able to get all of the way to the end of the game on novice (admittedly I'm not very good at fighters =D ).