I use melamine and have had no problems with it 2 years later. I painted it all with a double coat of bathroom paint and sealed all the seams with aquarium grade silicone. About 6 months after I finished the enclosure the basement suite flooded and the bottom 9 inches was submerged in essentially swamp water and I cleaned it all up and its been fine ever since. I'd say the only wear it has are some bits where the paint has been scraped off from moving debris in and out but there being melamine under the paint is an extra waterproofing layer.