The new style “ghost overflows,” drilled thru the back take up much less tank volume. They typically have greater linear length and tend to skim the surface water better. A downside is the requirement to move the tank further away from a wall to accommodate the plumbing going down the backside. You also need to drill a hole for the return(s) as well unless it is looped over the top (not a very attractive option).
The so called “reef ready” style overflow with drain(s) and return(s) thru the tank bottom can be positioned closer to a wall. But again, uses up more tank volume for the overflow box and may not be as visually appealing.
I won’t put holes into the bottom of my tanks anymore; particularly if they are open to the full tank volume. I prefer to keep the water inside the tank as much as possible.