I prefer LifeReef U tube overflows.
I really don't like having to rely on a powerhead to insure my main tank overflow is going to work. Scary thought considering how many powerheads fail to fire up upon loss/gain of electric power.
It's one of those .... if this one thing happens AND this other thing happens THEN this bad thing won't happen, scenerios.
Bad meaning the overflow fails and you start overflowing your tank while you're away.
Some folks run the CPR's without the powerhead and report okay operation.
Much of how well any overflow works is based upon the return pump flowrate, size of the tank's surface area and how it's plumbed to the sump.
I've ran U tube overflows for years and have never .. repeat .. never had one fail, or lose siphon. But I insure they have enough, but not too much flowrate running through them.
Up to you though - maybe some CPR fans will comment.