Either way, I think it is no great stretch to say that Ridley Scot is a vastly better director, and far more accomplished, than Christian Alvart. Although, who knows, maybe his previous movie, Curiosity & The Cat, was an instant classic. I doubt it though.
The character of Ripley is a fantastic one, and there have been few movies since that featured a stronger female lead. The fact that Sigourney Weaver would convincingly play such a strong character, and then go on to play far more conventionally feminine rolls like in Ghostbusters, is a fine example of her range.
Something also tells me that Pandorum lacks the spectacular pacing of Alien. Things are set up, allowed to brew, the tension is allowed to build before the aliens really show up in the film, and things are allowed even more time before any real violence even begins. Almost no other action movie, and certainly very few recent ones, allow tension to build like Alien does. Far too often it's the action that the movies are interested in, when it's the build up to the action that is actually so effective. Alien does it so very well.
Edit: Completely off-topic, but this is post #15,500. I think I'm going to go see if the sun is still out there.