I think a strength of this film is that it never takes itself too seriously. The subject matter is fairly dark, a love "square" revolving around a Vampire Hunter, his new assistant, his sister, and a vampire prince who is being hunted by his fellows so that a vampire lord may ascend and become a daywalker.
The love story between the Sister and the Prince is cute and touching at times. He falls for her instantly, and pursues her with vigilance and charm, not falling on the very clichéd vampire seduction. How does a girl resist a guy who risks his life just to see her during the day?
The movie does a good job foreshadowing the action. The hunters use an equalizer that quickly plays into the Hunter/Assistant relationship. The story shows us right away what the girls are capable of with a hilarious fight over a stuffed bear. Even Jackie Chan's bit part ends up being more than a cameo, as his characters reappears to help the heroes out.
The choreography was refreshing to me. I watched "Hero" recently, and while the story was excellent, the fights were laughable with people spinning around in the air like they just had a major stumble in zero gravity. In Vampire Effect the action ranges from, car chases, tug a war with a stuffed bear, a tight roof top chase with capoeria involved, an excellent all out brawl between the girls and the legions of vampires, and extensive use of grappling techniques which I rarely see in movies.
The use of caucasian actors for most of the vampires was clever, it fit into the plot as these type of beasts were supposed to be from out of town. They also looked tall, pale, and alien against the mostly Asian cast.
If you like good choreography, a bit of angst, and a nice dose of humor. I would recommend it. Don't expect Hero.