There are a few reasons I will always run a RUGF. First of all it has been running for about 35 years with almost no maintenance.
I find that microscope animals prefer to live in a substrait that has water running through it as the gravel is full of tube worms right down to the filter plates. It is almost impossable to crash the tank. The power has gone off twice for almost a week with no problems and I once had 24 local NY urchins all spawn at the same time, the water looked like Half and Half. Nothing happened. I had a huge carpet anemone die and rot while I was away and nothing happened.
I can re aquascape and disturb the gravel all I want and I can maintain the tank by stirring the gravel where I can reach every couple of years and sucking out the detritus. Only once after the first 25 years I did a good cleaning by moving the rocks to one side and stirring up the gravel.
The tank has never been emptied or crashed.
I have yet to find a DSB much more than 10 years old.
Do you know of any? I would be curious.
Have a great day.
Paul