I'm more inclined to vote realism as I try to keep out aliens and vampires from my "normal" saves.
Then again, I'd hate for the game to be super realistic, I like the Sims for being the Sims which is a different kind of reality. I mean, the game isn't the same without Grimmy, cowplants and ghosts. Or rocket ships and the bottomless invisible backpacks we call inventories.
Also, I do have several saves with aliens and/or vampires and I love playing those just as much. I really should get back to playing/writing my vampire story, I left off at an interesting point in the backstory part.
So I'll go for undecided/equally.