Before going into details it's probably worth mentioning that this is the only otome game or even a "visual novel with routes for different romantic partners" that I have ever finished at least a couple of routes from.
I have also only finished two routes so far, so I mark this as "played" and not "completed" because who knows when the goblins in my brain will actually let me finish all of it.

What a nice game! A love story for theater that stems from deep appreciation of the form and effort that goes into it. Love all the kids here, they're all my dearest beans (if we don't count Amber, Amber can go suck a wall).
I really love all the songs and performances in it, rewatched Hallelujah specifically like two dozen times.
Lovely exploration of gender presentation via your main character, a girl, learning how to portray a girl from an all-male cast. I especially like how Rhodonite is presented; I aspire to ever be as comfortable with myself as these characters are.
Also Sui Ishida's art is incredible, I always loved it and it's nice to see him draw something actually happy and cheerful (and not, you know, TG).

But, there's a but.
Like I said above, I have not really played games with character routes before if we don't count a 4chan VN from like 10 years ago, and playing JJ makes me think about how I don't quite like the idea of routes in a game where each router changes not the course of events, but merely the character who follows you through the main story points.
The game hides characterization, various minutiae of the world, whole story segments behind having to beat all of those routes. In order to truly learn not only the main lads, but the various side characters (lots of whom are very cute and nice and I'd love to know more) you must get all the Best Endings so you can unlock the True Route, the one where you can finally devote time to the most important person: yourself.
It preys on completionism and "gamifies" your experience: in order to get the Goodest Ending for the character of choice you must devote your entire self to them, develop your skills purely for them, spend your limited free time on looking for events with them that will raise your affinity so you can experience the coveted climax. I Hecked Up my first playthrough and didn't devote enough time to developing a Specific Character Skill and so only got a Good Ending but not the Goodest Ending, and the thought of having to replay the entire route because I tried to actually approach the school life gameplay like a human being instead of mindlessly obsessing over a single guy is a bit disappointing.
Coupled with the game having a True Route locked behind all the rest, your mindless devotion in each character route feels unreciprocated: despite all your efforts, your experience in that route is merely 1/8, each route but a mere step on the road to The True End.

Still, lovely game, I'll be chipping away at it and maybe update this whole ramble once I'm done.