Vampires. Other than there being more love and thought poured into them, there being more of a sense of empowerment, but not a sense of being overpowered, and the sheer amount of options and control leading to vastly different stories and playstyles...there's just no contest. Added to that, the powers are unique (each having their own quirks), even regarding similar powers to other occults.
Aesthetically, I can appreciate Spellcasters (not more, but at all). It's all flashy and interesting to look at. I wish they'd stuck with the Vampires formula of chosen spells and weaknesses, and done more with the gameplay. I also have my biases when it comes to magic within normal people, as it's always made things just too easy. Magic artifacts are fine, as they usually have limitations and focus.
I can also admit my bias against RoM, as from the first look at it (back when the gameplay trailer released) I knew I'd be disappointed, and playing it didn't help. I'd love to do a Simming Tip about it, but I can't yet get past that. I'd like to...but not yet.