MDF is not really that good, either. It is really heavy, it absorbs water like blotting paper (except for the MR or moisture resistant grade), it is a flamable material and therefore a fire risk (except for the FR or fire resistant grades), the joints will never look good, it will bow under its' own weight and absorbed moisture over time and it costs a heck of a lot more than sheetrock (plasterboard).
Plaster board on the other hand is lighter, cheaper (1/2 to 1/4 the price here in the UK), fire resistant, won't burn and is a doddle (relatively easy) to joint smoothly, easier to cut (straight edge and Stanley knife), easier to hang ("clout" nails and a hammer - no screwdriver needed) and to patch repair (if you ever do need to chop a bit out). Added to that if you need to gain access to the void under the floor the normal approach used in buildings almost everywhere is to lift the floorboards upstairs, not rip-out the ceiling below. If you are really concerned about damp then you should consider sealing the plasterboard and either "tanking" the cellar walls or at least improving the ventilation down there as you may well have another problem. For insulation plasterboard can be had which has a foil reflective backing.
Scrit
