How is it blasphemy to prefer Alien over Aliens? Both are EXCELLENT films of somewhat different styles. Alien is more atmospheric and suspenseful, whereas Aliens is a fun rollercoaster ride which also happens to beautifully add a bit in the drama department via the Ripley/Newt dynamic. James Cameron's artful direction allows us to get to know his characters just a little bit more (mostly because of the longer running time... mostly), but no one is ever lost in the fray when a single monster is meticulously picking them off with little to no defense against it as in Ridley Scott's Alien.
I just like the claustrophobic atmosphere created by Ridley Scott's film that much more, and applaud the film all the more for being able to present itself this way despite the fact that the ship involved is so freaking huge!