my favourite gotta be the library and it's mini-game and the wizard chess, it hasn't expanded that much in terms of locations, it's one location to explore and the other 2 are mini games.
what I like most about Pottermore on Playstation Home, you get to explore some locations of the wizardry world and key moments, I think for now they are exploring more the moments of Philosopher Stone first.
Hogwarts Library is beautiful.
I'm not into racing games, I like chess.
but since I have small amount of time in my ps3, it's not even worth it to go there (my brothers are using it, my little brother is here on vacations from university), so I can't explore as much as I would love to.
either way, non-ps3 users, you're not missing much, because the problem with non-ending stuff, is that you eventually you get tired of it.