Hot mopped pans are primarily a southwest thing. TX might be in that loop. Personally, I'd steer clear of them for either a conventional shower, or in Houston area, one that used a surface waterproofing membrane. That way, there's less to get damp. This means the whole shower dries out much faster and there's less chance for mold and mildew to grow. The hot, humid summers there can really benefit from a surface membrane construction technique. There are a couple of other approved systems than the Kerdi and Wedi mentioned. A Kerdi shower is sort of like putting up wallpaper over everything (thinset is the glue), then the tile. Nothing gets beneath the Kerdi, so you only have the thinset and tile - no mortar bed to get saturated (you still need the sloped bed, but that can be either their foam pan, or mortar (cheaper but slower)). Wedi is made from specially coated foam panels that you glue together with a special urethane, reinforce with a mesh, then tile over. Wedi is extremely fast to go together - you can have the bare walls and be tiling it in hours. The foam pans also have another benefit, they warm up almost instantly since there's so little mass. Nice in the winter. But, the best part is that there's so little that can get wet - no cbu on the walls, no mud-bed on the floor.