The only fish in a freshwater tank that I know of that really has a definite problem with certain substrate is the betta. They cannot have substrate that is sand or sand sized like EccoComplete as they will eat it. The little gluttons think it is betta pellets and will stuff themselves on it. But as you do not seem to have any of them in your tank I would agree that it is a matter of personal preference.

I have heard of people sticking plastic drinking straws in the sand to help relieve the gases that build up under them but the easiest and most dependable method of having sand substrate maintained is to get a Trumpet Snail and let it do the tunneling through the sand to keep it mixed up and from building up the gases.

Rose