I'm very happy about this rating. Only Alien 3 SE, Alien Resurrection and Predator 2 have got MA 15+ in Australia which means this will have at least the amount of violence/gore that they did.
I checked the Alien vs. Predator: Requiem profile in Imdb.com and saw that Taiwan rated it R-18, Finland rated K-18, Ireland rated 16 and last but not least, Singapore is given the rating NC-16. As for the UK and USA ratings? Go find them in this site yourself. It has been mentioned.