See, I thought sand would be easier to keep clean. I find it is with a lot of other setups anyway, as it doesn't tend to sink below the suface and the flow and fish movement keep it moving until it gets sucked up by the filters. Granted, there's some dead spots, but then that makes it easier to remove, if it's all in one place. With gravel, it obviously sinks between the gaps. Is this not the case with Oscars and similar sized fish then?
My only issue with sand and some of the bigger cichlids, is them picking up big mouthfulls, making a mess of the tank and dumping loads up the filter inlet...