These are two terrible films. The first one is just about watch-able and the lead female character is pretty good, but AVP Requiem is truly awful. Every possible action and horror film cliché is used, some of them several times. Characters wander off on their own, "bad" people get punished for their character flaws, while the good guys have some unresolved business which will lead to a neat pay-off at the end of the film. Heroes and villains spout terrible action film nonsense and both movies are devoid of any horror or tense moments.
The second film is slightly interesting as an exercise in film making. It starts out as a standard "teens under threat" slasher movie. Then about half way through the production team appear to have had a discussion about how good Aliens was and decided to remake it with their cardboard characters. Except without any of the wit, verve and slowly building tension that James Cameron added to the Alien franchise.
At least the monsters are mostly of the man in a suit variety as opposed to terrible, lightweight CGI sprites. Unfortunately that does lead to some odd moments when the tall and slender actors in the suits look rather ungainly and lumbering instead of the fast Aliens or powerful Predators they are playing. This could have been fixed with clever editing but even that is a disappointment.
Really, these two films are best avoided. Stick to the original Alien movies. Let us hope that Prometheus does not disappoint although early reports are not good.