I generally prefer metal over plastic for weight bearing items too, but I am really quite happy with the upper Ortlieb hooks. I have never heard of them failing and I like the way that they clasp around the rack bar so that they can't come off.

A friend of mine has had an Arkel front pannier come off twice, but that was on two cross country tours, so that was several months between times that the pannier fell off. And maybe it was user error those two times when the pannier came off? I think his Arkels are about 20 years old now, I do not know if they use the same brackets now as before.

He always used the rain covers, even on dry days. Photo below is eight years old.



That said, some people have had the Ortlieb inserts in the upper hooks fall out after a lot of use because the hooks have deformed slightly. Since I do not use the inserts, not an issue for me.

For my front Ortliebs, I fabricated my own lower hook out of 3/4 X 1/8 inch aluminum bar to use on Tubus Tara rack. And stretched some inner tube rubber over it to prevent the metal from damaging anything. Photo below has bad lighting but you can see it. The Tara has a larger than average tube and the regular Ortlieb hook did not work so well on the Tara when I also have that plastic hose over the rack tubing to prevent chafing.



But my other two touring bikes do not use the Tara, they use normal size tubing in their racks and the Ortlieb lower hook is used on those racks.