Back in the day i used hob overflows. What causes them to build up air is the lack of flow for the U-tube. If you increase the flow, you will see the air enter the U-tube and pass right through and not accumulate.I heard that the tube that goes over the edge can accumulate air that can cause the siphon to stop, flooding the tank and floors. Some people say that air builds up causing gurgling noises. I also don't like having something hanging on a clean rimless display. (yes, the other route has glass lily pipes hanging which look good when clean).
Certain models can accumulate air more than others. I found the clear round U-tube never accumulated air. The have a low flow rate so air goes in and out. Its the larger capacity U-tube is where you have trouble.