I thought both movies were pretty good. I liked both of them for different reasons. Underworld was a really good prequel that answered a lot of questions I had after watching the first two movies. First I thought HJNTIY was more of a chick flick but it got a lot better as the movie went on (still mostly a chick flick though). As a man it also caused me to reflect on current and past relationships that I've had with women at different points in my life.
Underworld

The fight scenes in this movie were really good and I found myself rooting for the Lycans. Even though in the first two I rooted more for the Vampires. Both Viktor and Lucian were those dudes in this movie. Overall I give this movie a solid B.
He's Just Not That Into You

This movie had some big names in it. Ben Affleck, Jennifer Anniston, Drew Barrymore, Jennifer Connolly, Scarlett Johansson. I think they all worked really well together. Sometimes when you have movies with lots of stars egos get in the way and it can ruin a movie. Anyway. The main advice given throughout the movie is: "If a guy wants you he will let you know." Sounds real simple but it can become complicated because women make it complicated. Anyway. Overall I give this movie a B+.