I'm pretty well read on both of them, but don't have much actual play experience and would like to get a better handle. I'm fairly certain either one would be an adult/mature game, owing to the systems alone.

Anything specific you're looking for?

I suppose I'd prefer to play monster hearts. I'm  looking at the vampire, but willing to play as anything, and as far as tone's concerned, I'm a fan of dark things, but with levity or facetiousness to them. Does that answer your question, or did you have other specifics in mind?

I don't have any experience with monsterhearts but I'll look at it. Honestly the games I have now are likely to keep me from being able to help you but I will toy with the idea and see how my schedule is.

Dark things/tone works. Did you want a setting like modern, apocalypse, or set in the past, fantasy?

Also plot wise, does anything work or is there something you like to see/play etc?

Monsterhearts is pretty specifically about supernatural drama in high school or college, based on things like Buffy. Most of the initial narrative is built into which characters are selected and how they're put together.

Apocalypse world is much the same except the base assumption is "there was an apocalypse" rather than "you're horny monsters in high school".