I have it but have only played it for a day or two. I bought it as an impulse, a few months ago, when it was on sale. It is fun, although a bit disturbing (you have to drink peoples' blood to restore your "mana/power").
One thing that I don't like is that the maximum resolution is too low for my taste, especially on a 21" monitor. It really shows its age on newer pc's.
Not sure if that will really help, since I never finished the game.