MDF is heavy. My back aches everytime I think of it. However, 1/2" is a bit lighter than the 3/4".
Thats my only complaint, well that and the massive amounts of dust it puts off when you cut it.
Hint: Be sure to use a quality dust mask when you cut it with saw or router (especially router).
Earplugs (or muffs) will not only protect your hearing from tool noise damage but also keep that fine dust from finding its way into your ears.
While Im wearing my safety inspector-wanna be hat, dont forget good eye protection. But you already know all this.