My favorite EP so far would have to be Late Night, with Ambitions being a fairly close runner-up. When it comes down to it, partying > work, sry2say. But yes, I love the new interactions and expressions with Late Night, and those are big things for me so this was a no-brainer.
By process of elimination, I'm pretty sure you could figure out that World Adventures is my least favorite. It's just . . . You can only go on so many adventures before it gets old. And it's kinda like it's own separate game in a way, as I don't think it's really integrated into the base game like the other two EPs. I do get a lot of use out of the photography and martial arts skills, though!
Of course, this is all subject to change next week. Generations, y'all!