Soft cut cuts the spark (or fuel) for a very short amount of time, revs generally stay where they are.

Hard cut cuts the spark (or fuel) for a longer amount of time, the car feels like its properly died and the revs drop noticably.
This is a last resort rev limiter that most people would never hit in their lives as soft cut limiters are set to work properly.

Hard cuts are generally set as an emergency higher RPM cut incase the soft cut doesnt have the required effect. On standard cossies they set about 300rpm higher than the soft cut IIRC

There isnt two types, it can be set to whatever, one cars soft can feel as hard as another cars hard, so cant judge one car against another and say "oooh yes, thats the hard cut limiter i hit there" as soift cut limiters are designed so you should never bloody hit the hard cut in the first place.