What is the difference between hollow metal doors and wood doors?

A hollow metal door is constructed of two face sheets of cold rolled steel sandwiching a core material. Typical core materials are polystyrene, cardboard honeycomb, fiberboard or urethane. A wood door can be solid wood stiles, rails and panels or two laminate sheets on a mdf core. Hollow metal doors are usually cheaper, but also usually only available in flush (a smooth slab). It was want a typical stile and rail door you should opt for wood.