I can only argue with metal body here: that'd vary on model-to-model basis. I've had a few thinkpads made of plastic, and they're fine after a few drops here and there, and hinges are alive and well, also I've seen some (mostly new-ish) laptops made of literal aluminum foil that are bent AF; what's even worse, one wasn't even what they call unibody, i.e. the frame was sandwiched of aluminum shell and a piece of crappy plastic with heat inserts for screws → after like a year of normal usage those inserts literally broke off with the surrounding plastic.

The latter one was some ultrabook by HP. Namedropping here 'cause I have some personal issues with their products, so, frankly speaking, fuck them in particular :)