That's could be debated forever, but I'd opt for a sump....Yes can hide your equipment, and extra water volume, but also the sump could be a safe haven for a picked on fish, expandable filtration area. I have the opinion that having a sump makes it safer and easier if your dosing that your dosing through the sump and the solution can be diluted and slowly added to the DT instead of a max dosing in the tank. Water changes I feel are easier done through the sump; gives things a chance to mix outside the DT. Just my .02