I prefer MKII even though SF may be the more popular game across the entire franchise as akumushi said.
To me, it had slightly better graphics, the gameplay was much improved (doing natural movements for weapons etc. instead of the SF way of doing a half-circle with the joystick and pressing 2-buttons simultaneously), the fighting engine was much better and more well rounded, and of course FATALITIES and babalities!
How can you resist a baby Baraka.