The whole alien vs predator thing is a total mystery to me. It is a sequel based on a film based on a video game that was a merging of two different series of films, neither of which seemingly have any link to each other. One of those series started of as a brilliant clautrophobic space adventure, which developed into a quadrilogy (which isn't even a word, they seemed to just make it up) of widely varying quality. The other series starred Arnie, which is bad enough in my mind.
The Californian public decided to vote Arnie to govern over them. He was a terrible actor, and a former body builder, and now he governs a State?
The whole thing totally confuses me, and I hope that the film does terribly at the box office.
But, I think that there is a great deal of marketing potential in taking two stars of unrelated films, and pitting them against each other. I fancy Batman vs Hal, or Super Ted versus Satan.