Alien or Predator, This is a very interesting question because both bring a lot to the table, The predator is such a great creature from its design to the vast selection of weapons, and nothing is more iconic that its thermal vision and voice mimicry its truly a terrifying creature but I have to give it to Alien the fact that the Xenomorph is truly terrifying (Just play Alien Isolation to see what I mean) Plus the Alien Universe in my opinion is way more in-depth and diverse. There is so much to explore with Alien where predator there is not as much outside of the few films and comics and besides Predator and Predator 2 there is not as many good films where with Alien I love the first three and I enjoy Resurrection even if its not a good Alien movie.