In English I like the peppies best. they're always friendly, enthusiastic, and seem to have the most dialogue. I liked peppies in past games, but now I absolutely love them! I also like what they've done with the crankies, making them more like sweet but grouchy old men, and the smugs, who now seem more like slightly-dorky, uncool dads more than anything else.
In Japanese, I like the snooties and lazies best. The snooties seem almost like uchis in that they're quite caring (but kind of in a no-BS way) and big-sisterly/motherly. They seem to care about you and give good advice. Lazies are really funny and just dopey and sweet in Japanese, and they don't talk about bugs at all! (Big bonus for me, lol.) Normal villagers also seem more talkative in Japanese, which I really like.