FWIW, I ran a siphon fed overflow on my 55 gal FW
for 5 years and it never failed once.
It was a pain to get started though, I'd have to hold plastic over both ends, fill the U tube with water, and then (holding the plastic) flip it upside down and into the skimmerbox/overflow box. If enough water spilled out during the flip, I'd have to re-fill it with water adn try again.
Sometimes a bubble would form in the U-Tube b/c some water spille dout
Also, If I turned the pump off, but forgot to break the siphon, my sump would gradually fill up and overflow if I forgot. It didn't take long for me to learn.
I miss being able to dump buckets for PWC
into the sump tank, but other than that I don't miss the siphon/overflow/sump at all.