Both are excellent drivers, I think it more depends on how the rest is designed (xover, shape of the enclosure, etc.)
But if I could choose, I would go for the Morel.
I don't really think a metal faceplate improves the sound, allthough a crappy flexible plastic faceplate can degrade bassresponse when you don't put the tweeter in a seperate enclosure. But as far as the quality of reproducing high frequencies I don't think there's much difference between a metal or plastic faceplate.