Requiem Second Edition is pretty solid as (just to keep things on topic) an example of what I understand to be a “high-concept sim.” The mechanics are a little complex, but they do an excellent job of mechanically expressing the fiction they represent. And it’s very focused on emulating the descent into monstrosity angle, so… maybe not so appealing if you were more into the “superheroes with fangs” style of play than the “woe is me, I’m eternally cursed” style. Not sure what’s up with Masquerade 5th edition (or “VV” as they called it) because, again, I bounced off with the change of publishers. But I’ve heard that they actually did a pretty good job of modernizing the mechanics.