MDF is high density and normal particle board is a little flakier, most cabs originally used a resin based form like MDF. I have done both with the laminate, on my current conversion, one side the laminate came right off, the other did not with two coats of paint on it. I was laminating mine, so on the wood side I used a 40 or 60 grit paper first to get through any old adhesive then re-laminated it. I scored the old laminate with heavy girt sand paper then scored with a dremel tool so my contact cement would ahere, worked awesome.
If you plan to paint follow up the rough sanding wtih a 120 grit or so and that should smooth it out well. Others may like to get it even smoother for paint. You dont need to sand it down a ton, but you will have best results if you remove any old adhesive first, fill holes and sand to smooth. Your paint will only look as good as the surface underneath it.