I honestly only watched this because of Krysten Ritter - who may actually be a vampire - but it was better than I expected. Alicia, and Krysten play two vampire roommates living in New York, Goody, and Stacy, respectively. Vamps has a very '90s feel to it, and it is foremost a comedy. When there are moments of vampire activity, it's used to remind the viewer that this is indeed a movie about vampires or for a quick laugh, but thankfully does so without going into parody.
What surprised me was how much of an emotional arc the journey has: Goody, and Stacy have almost a sisterly bond, which becomes more like a mother/daughter bond toward the end, and I really, really wish that would have been developed more in the story.
The first act is the strongest portion of the film, it begins to fall apart toward the middle, and the end is a bit weak. There are some bad CG effects - which may have been intentional since this is a comedy.
Overall, I thought this was good, but flawed. I totally loved Goody, and Stacy - mainly Stacy... be still, my vampire heart!
In some respects it just had too much on its plate. I needed more done with the antagonists: Cisserus, and Van Helsing. This is such a simple story - it's basically Romeo and Juliet, only with vampires - and it didn't need the rest of the padding.

Anyway, if you dig '90s, female-driven comedies or '80s vampire comedies give it a watch. Keep the expectations low. Don't bite rats - rats are friends, not food. Krysten Ritter is a goddess.