I overall would recommend Beastars. The characters are really cool and enjoyable. Despite some flaws, I found the world-building pretty fleshed out and interesting. As for bad things: the ending is kind of unsatisfying, and some things are introduced but later never brought up again.

There are two "parts" to the manga: first, a lighter section taking place largely in the school; then, Legosi saves the city. Despite the huge shift in the gravity of the situation, Legosi is still the same character: he's shy and weird (think: white knight), which doesn't change even as he becomes (mentally and physically) stronger (well, maybe a little, but it's reasonable). The same goes for other characters, such as Louis (he's sort of arrogant at first, but then becomes more humble); every character becomes "better", but they are still very much the same character. The way the characters grow feels very natural and very satisfying: the whole time I was cheering on Legosi (and his friends).

The many different species and in particular the carnivore/herbivore divide really aid in the character development. Legosi's "thing" is that he is a large carnivorous wolf but is very much a pacifist and feels very guilty when he feels his carnivorous/feral instincts bubbling up. There also a lot of small details about the species that make each character unique, although they often feel like a "deus ex machina" to advance the plot in a certain way; there will be a sudden plot twist, and it'll be post-hoc explained through a flashback/world-building sequence.

That is basically my main dislike. It applies not only to the characters but to the world-building in general. For example: Legosi and his friend Jack are talking about history, and Jack brings up that the "carni-herbi war" was just ended by a big whale; and then it cuts to the Beastar talking to a whale. Nowhere are we hinted before that there would be a whale, or that it would have so much significance to the plot (well, it still didn't have that much significance, but it was very significant to the world-building; its inclusion made the world feel less believable and consistent).

Other examples (spoiler: rot13; just read the paragraph below if you want to avoid spoilers): Yrtbfv vf tbvat gb or chfurq vagb gur jngre gb qebja, lrg ur vf irel pnyz nobhg vg. Vg gura synfuonpxf gb uvz gnyxvat gb uvf frny sevraq, jub grnpurf uvz n pbhcyr "Frnfcrnx" cuenfrf, juvpu Yrtbfv fnlf gb trg uvzfrys fnirq ol n frn navzny. Nabgure rknzcyr: Bar bs gur ureoviber znva punenpgref orpbzrf gur yrnqre bs n pneaviber tnat, naq juvyr gur tnat erfcrpgf gur ureoviber, gurl fgvyy unir pneavibebhf vafgvapgf. Bar bs gur tnat zrzoref jub'f rfcrpvnyyl pybfr gb gur ureoviber tbrf ba n qevir jvgu uvz, ohg trgf fubg ol nabgure zrzore jura ur tvirf va gb uvf vafgvapgf. Gura vg fhqqrayl tbrf gb n synfuonpx bs gung svefg zrzore gryyvat gur bgure zrzore gb fubbg uvz vs ur qbrf fbzrguvat yvxr gung.

In each of these examples, the flashback goes to a time-frame that is within the plot, so it feels very unjustified; that scene could've simply been added earlier, which would've also been nice foreshadowing. Sometimes it flashbacks to a scene only a few chapters prior. It very much feels like they are "telling" instead of "showing". It's pretty annoying, since for the most part the world-building is very nice, with how the society functions with all the different sizes of animals and of course the carnivore/herbivore tension.

If I had to summarize very concisely what the main appeal was to me, I'd say: taboo love and self-destructive violence/self-hatred. The entire plot is motivated by Legosi's (a big carnivore wolf) attraction to Haru (a small herbivore rabbit). In their society, interspecies love is taboo, especially carnivore/herbivore relationships. (It's the same reason why incest porn is so popular.) For the second: Legosi hates himself for being a big wolf and having these carnivorous desires, and in his big fights he's gets pummeled a lot; he always wins by some slim margin, but not through any spectacular gimmick but rather just like his own willpower and principles. I don't know if the following is really relatable (I have seen one Instagram post (of a Tumblr post) that suggests it is), but: as a child I would have make up a lot of really tragic romantic fantasies where the protagonist would constantly suffer for his love. I mean that was also the reason that I watched Sword Art Online (Kirito and Asuna's relationship), even though in retrospect and as-I-was-watching-it-spect it was pretty cringy.

I guess I should mention the art. I don't really focus on the art as much as I should've; especially since I binge-read it over the span of 8 hours, I sort of passively absorbed the art as I was reading the text. But I guess the art is pretty nice. It is sort of "haphazard" in the first view volumes, but it quickly improves. I guess I like the furries; I like the character designs. Maybe I'm just socially inept, but sometimes I have trouble differentiating the characters in manga with regular people and have to just rely on the hair, so having literally different species helps. Although, it's sometimes hard to tell which gender a character is because they're all animals.