Well the way I figure it is a movies can be broken down into one of three catagories.
good fun neither
I don't think there's much chance of AvP of falling into the first, but I'd say its got a good shot at either of the last two.
A movie is an experience and I try not to let things like continuity stand too much in the way of that experience, after all I'd rather enjoy my money spent (even if on something trivial) than be nitpicky and ruin the fun for myself.
[edit: Just thought I'd expand on the whole good/fun thing. I think a lot of people don't enjoy as many movies as they could becuase they want to lump the two together. But really they are very seperate issues. I'll give a couple of examples (based on my own opinions anyway). Schindler's List is absolutely not a fun movie, but is is a good movie. On the other hand Army of Darkness is not at all a good movie, however it very fun to watch. Does that kind of difference make sense or am I talking nonsense?]