I think many people poo poo MDF because they think it is beneath them, and not a 'true' medium to construct with.
This is simply a fallacy, and MDF is in fact a very beneficial to ethical work, especially concerning the environment.
Easy to work and very stable. It is in fact the ideal material to veneer on to, and excellent in that respect for large sized tables.
It is ethically sound to veneer, especially in the cases of highly figured or exotic timbers.
I admit to having this hang up when I first started, but 3 years into college my thinking had changed and the benefits of it were clear.