I will start off by saying, I really enjoy this manga! It's actually one of my all-time favorites, because it's got school life, slice-of-life, dorm mates, rivals to best friends to lovers(sort of?), and a fun supporting cast; if you like Hana Kimi (which is my absolute most-loved manga ever), this has a very similar feel in a lot of ways. It definitely has its problems, but for me personally it is overwhelmingly worth reading anyway, because it makes me happy and the good outweighs the bad.
All that being said, it's...old. The art style is dated, and there's a fair amount of sexist (and a few kind of racist-feeling) bits, i.e., every woman has incredible housework and cooking skills, unless she's a career woman with a more 'brash' personality. (Any time Ayako's job is brought up, they make a point to mention that it's weird that she's a detective and not just a traffic cop, and also that she's a woman and shouldn't have to work, and also also that she probably only has this job to keep Kiyomine out of trouble.) Also, this might be a cultural thing and not a dated thing, but bullying gets brought up a lot as well and most times the characters' response to the bullied kid is 'well, it's half your fault, did you even try to get along with them?'
As far as the plot goes, it is slice-of-life, so there isn't much of a plot; we're mostly just focusing on the characters and their lives. When we do have plot, there's a lot of threads that feel random (TWICE, we explore a side character with terrible family issues that Takara has involved himself in), or that are left dangling. Like, we compare Takara to his mom all the time and it's constantly brought up that she passed away when he was little...but no joke, we NEVER find out how she died. Presumably it wasn't sickness, since Takara's hospital trauma seems to stem solely from his grandmother's passing - and, despite all the terrible situations Takara finds himself or the people he loves in (fire, kidnapping, car accidents, etc.), he never brings up anything like 'ah, my mother died this way'. It's just weird because her being dead comes up over and over again, and yet this aspect of it is never addressed. Additionally, despite the story being character-driven (and while I love most of the characters), I don't know that any of them grow that much throughout the course of this story. Kiyomine and Takara's relationship gets better, Takara becomes more willing to be affectionate and depend on the people around him, and Kiyomine opens his world a bit more...but I don't know that anyone is in any way a new person by the end (except maybe Touya, but he had a rough start; and I guess some of the new first years introduced towards the end have some improvement when we leave them). If you're expecting someone to become a better/more improved version of themselves throughout, this probably isn't the manga for you. For example, does Kiyomine ever apologize for anything, ever? Spoiler: No. ...Okay once, but for something that was arguably not even his fault.
As herosusan123 said, this is borderline shounen-ai; I think that's partially because this manga is definitely a product of its older time, but we never see Takara and Kiyomine kiss (it's definitely heavily implied, but the panel always stops right before it happens and cuts away - and the kisses are also usually marketed as Kiyomine just messing around with Takara). They also, even up to the very very end of the manga, never define their relationship...AS a relationship, and even both think about getting girlfriends at one point or another. All that being said, I am a sucker for couples where they're each other's 'special exception', and this manga checks that box HARD. There's a line Takara has about how being with Kiyomine is 'easier than breathing', which hits me in the chest every time I read it, and another where Kiyomine calls Takara the other half of his soul (and that he makes him feel like he can be more emotional and open, like Takara). They are integral to each other, absolutely inseparable and better/happier together. Also, all the casual cuddles and general skinship brings me joy.
[color=Red]tl;dr: It's old, it's slice of life and mostly plotless, and the main relationship is arguably not romantic at all. But I love it, and I've read it in one sitting about three times through already. 🙂[/color]