i had been told there are more chemicals in MDF than in chipboard (which is what is under the melamine) but cant be certain on that, and i have sen a home made MDF cabinet that definitely was not withstanding the test of time and moisture, so maybe its ok for experienced builders to use, but i'd say for a first timer perhaps something that requires less 'finishing' -like a laminated/veneer chipboard- would be better?
Also, because MDF is a much denser particle board it is a LOT heavier than the melamine.