Looking at some projects, don't use much mdf, and when I do, it's usually home depot onesy-twosie kind of stuff. In my CNC communities there is a general regard fro Plum Creek super refined MDF as "the best". My big big big (supplies the local lumber companies) supplier carries Roseburg, which has a variety of optional specifications from flame retardant to "medite" to "medite II", to "medite 3d" and such as here??.?