The difference is pressure - you have to be used to typing softly on newer Apple keyboards or else you'll soon get pain from the low travel.

Learning to do so can be very rewarding, since the low travel allows a very fast keypress. Typing softly in general is great for finger pain, and mechanical keyboards allow one to use more force but retract before connecting with the keyboard's backplane (bottoming-out in keyboard-speak) and causing the louder "clack" after the initial actuation.