I love Aliens for many reasons, but the main one is that they are by far more eerie and, well, scary. You could most likely reason with a predator, and get them to spare/work with you. You absolutely can not get an Alien to follow your will. Then theres the fact that aliens swarm, creating a very ominous reading on a motion tracker. You check the tracker and only see one dot compared to checking and seeing a solid wall coming towards you. To further illustrate my point, think about how well you could barricade a place to stop a Predator, then think about Aliens. With a Predator you just seal up the hallways, lay down a few sentry guns, and pray they don't have very good explosives. With Aliens, you do the same thing, but just when you think your safe you realize that A) Your sentry guns just ran out of ammo, B) The power just got cut, C) Now they're past the barriers and walls without even being seen, D) HOLY S*** they're in the ceiling!