Interesting question, probably with no straight forward answer because in the end much of this comes down to build quality. There is also precision to consider. Unfortunately strength/rigidity and precision don't necessarily come in the same package. Ebony wood cameras are said to be very rigid and precise. Linhof metal cameras are said to be very rigid and precise. Etc.

The great frustration for me with this stuff is not being able to just go to a store and try them. Ebony, Linhof, Sinar, Arca, Toyo. Who knows. And this is big ticket stuff, even used. Which one will best serve my needs? Will I get what I'm told I'll get? You have to buy based purely on specifications, "research" and opinion, and speaking for myself, no matter how much time I spend researching and how hard I try to make the right move, I end up going in circles, and I've been disappointed.