Even though I have aging off due to rotational play (in part I don't like them to die either) I'm used to "immortal" sims but for some reason vampires start to bore me. I'm guessing it's my style of gameplay that gets in the way. I love spell casters and so far werewolves. I like mermaids but sometimes forget they're even an occult sim.
I've never felt they were nearly as powerful as my spell caster sims and other than creating side drama I don't play as vampires anymore. They're just friends or enemies of my other sims. They have too much time. I prefer a little pressure to keep my sims needs met and outside of thirst they really don't have much else... making them a day walker makes them feel less like a vampire to me. In general I guess I don't favor them and that's fine. They exist to assist in story lines for me