Both gel coat and acrylic walk-in tubs are made with fiberglass reinforcements. The main difference is the material used for the surface. Gel coat walk-in tubs are made from fiberglass with plywood backing and are just as durable and long-lasting as acrylic tubs. Acrylic tubs, on the other hand, are made from one material that allows for surface resistance to mold and mildew, which makes them easier to maintain.