Presonally I like sand in my tankz, more natural display tank look. But I can see the logic behind having a bare bottom tank, it does look nice, easy to clean, and simple. If you notice, a lotta people will use it for rays and discus since they are so touchy about water quality, and its easier to keep the tank in check that way. Also, its normally with large fish, 10" and above for the most part. More waste, easier to keep clean.