Plastic combs might be Cheap, Versatile, and Long lasting, but they are far inferior to wooden combs. This makes them the worst choice for your beard. When you comb your beard they produce static electricity, causing it to become more entangled. Plastic combs are mold-pressed, which in the manufacturing process, leaves microscopic jagged edges in between the teeth which snag and pull your beard hairs. This increases the likelihood of ingrown hairs and split ends.
Synthetic hair brushes lack the ability to trap your natural oils and beard oil. Leaving your skin dry and itchy.