Zombies will always be my number 1 occult. But out of the two I'd have to choose vampires. I'm actually surprised how many people prefer spell casters (though that's not a bad thing)
The dueling is amazing and innovative, and the realm is pretty but aside from that they alway felt like regular humans who have a bit of magic. I wanted them to feel a bit darker, more witchy and occult like. The magic spells are kind of meh and simmingal pointed out the problems I have with evil ones. No magic is ever performed anywhere on it's own so there's no way to even make a world feel magical. Familars are a cute idea but I wish they expanded on them a bit more.
I do like the curses and nightwraight is the best part!! I cheat him to haunt my sims just cause he's so cool lol.
On the contrary I have no complaints or dislikes about vampires. I think they were perfectly done and I'm never without a vampire in my gameplay.
Most of my sims are a mix of vampires and mermaids. (Soon to be werewolves I hope?)(and eventually zombies ?)