I'm not so sure the advantages outweigh the disadvantages. You only get to play during the night, so potentially 50% less than a normal player. Also, you have to attack other players, if they have some garlic on them, or have chosen a god which happens to have a cross pendent, the vampire will be severely hurt by simply getting near that player.
I'd say the disadvantages outweigh the advantages, so you'll end up using all advantages just to survive, rather than other players who use their skills to gain materialistic things, increase their bank balance etc. Of course, I could be wrong, but then we know what the ultimate disadvantage could be.
