The SL and the Compact is the both uses automap universal, both have semi weighted keys with aftertouch.
The main differences is the amount of controls, the SL has sliders, more buttons and knobs. Whereas the Compact has less button and knobs, but it has bigger drumpad and a speed dial function.
Also the SL features touchpad and mod/pitch joystick whereas the compact just have the traditional mod and pitch wheel. And most obviously, the SL has 2 large display and the Compact only have 1.