In my house losing syphon is a big deal. That means upward to 25 gal
on the floor should the tank lose syphon the pump in the sump will not stop. So it will overfill the tank and the water winds up on teh floor.
The c shell style do often suggest a powerhead to help keep air out of the C area. Its important to pick a relyable powerhead. In my book stay away from RIOs for this function as they are not overly relyable to start up when you neeed them to be.
U tube overflows dont need the powerhead to keep the syphon but the down side is they are a bit more bulkyi nthe tank as they have a 3/4" - 1" hose going up and over the side of the tank vs a low profile but long C shell type syphon.