JJBA pt 4 is tied with 2 for my favorite. Fights have been top notch, characters are fun, pacing is great (part 3 was stretched out way too much at times). I also like that there are a good number of episodes that are just random misadventures involving stand powers and not every single person the main characters meet is a villain like in part 3, it makes the whole thing feel a lot more down to earth. And Kira is an A+ villain, the way that it introduced him by having an episode from his point of view made him a whole lot more interesting and relatable (well, relatively speaking) which makes him all the scarier.
Harem being a common element of anime is one of those things that I've just kind of become numb to and stopped noticing, along with half of shows being set in high school. Konosuba is my favorite that is a harem but Monogatari is probably the one that's done the most interesting things with the genre.