I am a little more than half way through the first season of JJK and find it to be rather unoriginal/derivative, rushed, and with unengaging characters. I don't feel particularly connected to any of the characters and feel that the story is speeding ahead while leaving character and relationship development behind. The world-building is average, in my opinion, but since I have invested some time into watching it I am a bit curious to see where the story goes and think I might finish the first season. I have heard that things get better later in the first season, so maybe I'll stick with it.
I'm also watching the show dubbed and I am generally quite biased against English voice actors, so that is definitely negatively affecting my viewing experience. Generally speaking, I find that English voice actors come across like they're trying too hard with tone and that they lack nuance. This is also the case for me with JJK. To be fair, I have watched segments of the show in Japanese with subs and found it, as I expected, to be more bearable. Still, I think if I watched it subbed that many of the other issues I have with the show would still remain.
I really enjoy other shounen anime like Naruto, Bleach, and Tokyo Ghoul. To an extent, JJK feels like a mix of these, with some of the gore of Tokyo Ghoul, the world-building of Bleach, and the characters and character tropes from Naruto (e.g., one character in JJK who sends to be a rather blatant rip off of Kakashi from Naruto).
Despite there literally being whole chunks of episodes dedicated to exploring characters' motivations in JJK, the reasoning behind these motivations feels rushed, hollow, and/or flat, and adds to the sense that the show is basically a parody of other shounen and again, is simply rushed. For example, there is a discussion at one point about whether humans have souls, and I think this is supposed to add gravitas and engagement to the show and to build on character development, but instead it comes across to me as largely half-baked philosophy that has (so far) very little pay off.
Also, I personally find the animation a bit clunky. The character design isn't as good as, say, Bleach, and the animation is a bit choppy. I don't know if it's an issue of frame rates or what, but this is particularly telling for me during some of the fight scenes.
I don't usually write reviews, and let alone negative ones, but I felt the need to share my perspective since many of the reviews I've read don't resonate with me. And writing this has actuation exposed more reasons that I don't like the show than reasons that I do like it.
In all, if you're not too picky about character development, world building, or plot/pacing, but want a typical shounen, then you might want to check this out. Otherwise, I'd say to pat it and go back and check out other anime like the ones I listed above. If I end up watching more of the season and having my opinion dramatically shift, I will edit this review.