Oh I see. So what kind of moves make sticks better then and for which fighting games?
Stick is better when diagonal directions such as UF, UB, DB, DF. In games such as SF, diagonals are used frequently in Quarter-Circle-Foward, Double-Quarter-Circle-Forward, 360 and 720 rotation moves. In MK9, you will use diagonals during instant air moves, such as Mileena's air sai, Liu Kang's air fireball, by performing UB, F, FP. You'll have to press the two diagonal buttons on pad. For me, I feel my thumb is too big and I can't consistently hit the PS3 dual shock direction pad as easilly.
I also find that I am more consistent performing any "Test Your Might" and Johnny Cage's corner combo: B+FK, dash, BP, BP, BP, BP, BP, BP, FP, FP, Nut Cracker more easilly on Stick due to the ease of multiple tapping. I feel you have to work much harder on a PS3 pad, this in turn strains your hands quickly. Plus, if you have arcade sanwa buttons your button response rate is even better.
The input of MK's special moves makes the game very good on keyboard. Probably better than pad. You can just tap the moves and dial in the combos. An eagle eye PS3 converter, designed for First Person Shooters should be able to work, you just map the buttons. The only issue is the keyboard might not be able to negative edge too many buttons.