According to the
Tomato Meter, Kangaroo Jack got a 9% rating and National Security got a 14% rating. That makes them both rotten tomatoes, but I guess National Security is slightly better, especially if that's the type of movie you're interested in.
If you're wondering, RottenTomatoes.com archives reviews from major media sources and from other lesser known media sources and then averages the score to get the Tomato Reading. I like the site because you get an average of reviews and not just one person's review, so you know what the majority opinion is.