I respect alot of tension and shadow-suspense that Hawks does, but Carpenter makes his tale more frightening, more gritty, more about humanity turning against each other in paranoia & fear, and memorable FX shots.
I just had this conversation in PM and while I can't argue that Carpenter's version is vastly superior by virtue of its special effects and its truer to the story ("Who Goes There?") and because of that fact it adds more to the paranoia, I still prefer the '51 version. Its dialogue, so fast paced and expertly delivered, is without peer in any sci-fi flick and its score brilliantly adds to the feeling of cold and desolation. Its always been THE perfect stormy night movie for me.
I think, too, that since I "grew up" with the '51 version, it has something to to do with my preference.
FWIW - I like Carpenter's version very much.
