If I'm not mistaken, the UK, Canada and Australia and even Ishapore of India made inch measurements FALs. I also believe that the H&R made FALs were also inch.
Everybody else went with metric - including the Israelis who have been selling us their parts.
As to which is better, given equal workmanship and materials and ammo diet (and care), they should last the same. Go with parts and magazine availability. It's easier to keep your FAL running that way.
4v50 Gary