The tl;dr:
* Good pacing overall, nice balance between mystery and comedy
* Fine acting, distinct personalities and interesting background stories for the main cast
* No Romance!
* Strong female character, who unfortunately gets pushed out of the plot later
* Important message; good portrayal of diversity (considering it's Chinese)
* Ear-catching OST

The first episodes start with a strong comedic vibe, which is sometimes even stapsticky, after which the drama progressively gets deeper into the mystery of what happened three years ago.
I liked how this change happens gradually, the audience gets lured in with seemingly simple detective cases, and glimpses into the background stories. Only slowly the bigger picture begins to emerge, and it's not until the very end that we know all of the important elements. And on the way to the story's climax, the comedic elements are not lost -- the whole show feels well-rounded in its pacing and in the balancing of the different elements.
There are no episodes that feel dragged out, nor does the story ever feel rushed.

All of the main characters are incredibly well portrayed. Usually with costume dramas, especially those set at court, with all these similar uniforms and hats, it takes at least three episodes until I know who is supposed to be who. Not in this drama! Not only have the members of the Judicial Court all distinct personalities (more on that later), but each character has his (or her) very own body language. Even when they do nothing but sit or stand around, it's possible to recognize each and every one of them, even from behind.

No Romance! Always a plus, if the writer doesn't force a het romance into an otherwise engaging story, just to prove that there is no homo-romantic attraction between the main characters.

I loved Vice Minister Shangguan from the first minute -- finally, here is a female character who is not a simpering, love-sick and annoying girl but rather a strong woman who fought for her right to have her own life. In a sexist society (other characters even comment on this), she opposed her parents' will and got into a position of power as an official. Her office which is overflowing with scrolls and paperwork shows how hard-working she is. She must have had a hard time navigating Palace politics, as a woman and sole vice minister -- always on the outlook for people who want to sabotage her and her work; and we get to see glimpses of how she did it in the first episodes.
I also loved how her appearance underlines her character -- she's wearing sensible clothes, her make-up is modestly done.
All of which make the one thing that's really bad about the drama even worse: When things get serious, she's getting shipped off, for her safety, or, as Li Bing would put it, "for her own good". Why? She's certainly not weaker that, say, Cui Bei. She's not less experienced in intrigue than Wang Qi or less clever than any of them. So, why? Only so that when it gets serious, she can't "steal" the spotlight from the men. Plotwise, it would have been very much possible for her to be an important part of the team.
This is the one reason I deducted half a point from the rating for the category "story".

One big point in the drama's favour is that it shows us how important it is to see others as a human being -- what it does to a person if they are dehumanized (whether revered as god or reviled as monster) and how it makes us more human if we are kind to one another. Connected to this is that the acceptance of diversity can only strengthen us. (Which makes it even more regrettable that Vice Minister Shangguan is not part of the team!)
The team of Ming Jing Hall are very different people, not only is the boss half-human, half-cat, there's also the superstitious ex-soldier, the "diplomat" with a fondness for cross-dressing, the bookish man who always brings bad luck, the bumbling country boy and even a foreigner!
(That's one aspect that I found astonishing, there was actually very little nationalism in this drama; usually Chinese dramas are all about how great and heroic the Chinese people are -- here they are the aggressors towards another country, while the presumed antagonist just wants ... well, that would be a spoiler.)
Only by working together, by not just accepting each other but also recognizing each other's strengths and quirks, can the team solve the mystery and get justice for those who have been wronged.

Overall, this is an engaging and well-acted drama that made me laugh, and made me cry, and had me on the edge of my seat until the last minute of the closing credits.