which would you fear more?
Well aliens would most likely be bound by our physical laws so they'd have some exploitable weakness, where as demons are magic which would mean there's a strong possibility they may not have an exploitable weakness that I'd be capable of figuring out.
JUST For the the Heck of it.
If Demon's were attacking I would be scared to find out that HELL is actually real but would hold on hoping that Angel's and Heaven was true as well.
Now the difficult part
Alien by definition is a foreign entity so technically a Demon is a Alien because a Demon is definitely a foreign entity.
So specifically saying a Alien from another planet or from another world(not hell) like the one's from popular culture then
I would be afraid of them in the aspect of being the unknown. How powerful are they? Can we defeat them? Do they have a weakness?
So I guess Alien
( + )
Pretending both are real -- I would choose aliens. If they are here -- it's probably for colonization or resource taking. If it's purely for true communication, they would be intelligent enough to make contact without physically being here (since we can find them, I am assuming they found us which means they are technologically more advanced that us (although intelligence can be subjective).
Plus, demons would be a lot of fun to hang out with.
https://www.facebook.com/ReloadedFilms OMG!!! I have found a short film online that combines both elements!! it's insane!!! its like a mixture of Alien and some kind of mutant creatures!!! you guys have to check it out! it's called Icarus Down!!!
I think we need some kind of more distinct traits. Some Daemon types only live within mortals, and then escape when their character flaws get out of hand. Or only make deals with people.
Some aliens are good.
On terms of "basically a minotaur copy vs the one thing from that movie in the late 70s" I think aliens are scarier. Because we're used to demons more. But in a fight, demons are scarier. Because they're not mortal. Furthermore, in a long term battle (character flaw setting) the demons are scarier. Because aliens just use that stereo-typically as a tactical front to dominate. Demons try to make the character do something they hate. Or twist their emotions and traumatize them for the sake of it.
((first pooooost ey comicvine how u doin))