I read this a couple of months ago(it should be noted that i read all chapters in a day, It's addicting), and since then I have found myself rereading it more than once, even if it was just some of the chapters.
While I understand what people are saying when they give this a 2/10, because yes, in some ways it deserves that, the fact that I've even reread this I think says that its pretty damn enjoyable.

The story is simple: A studyworm meets a popular badboy and they fall in love, with a lot melodrama happening all over the place. I personally love melodrama, but it is of course not for everyone.
The relationship between Tsubaki and Kyota is developed very well and honestly the ACTUAL romance in this manga is some of the best I've seen. It's great, cute, sad at some parts and just overall amazing. You can see that they genuinly love each other and that its true love for them. And it's as realistic as a shojo can get.
There were some things that really made frustated though:
1. There was pretty much no development on the sidecharacters. There was also almost no appearances for them. Sure, Sakura got a bit more mature but thats only natural since this takes place over 3 years. Also Tsubakis best friend(forgot her name), she was always just kinda 'there'. Especially in comparison to characters like the-hairdresser-dude(forgot his name too), and random-love-rival-that-loves-astronomi(and hers) towards the end. It could have been a lot better if they had an bigger impact.
2. (Spoilers ahead:) Something that i always found weird and pretty unrealistic is that Tsubaki gets almost-raped 2 times. Even weirder is that both times, she just brushes it off like its nothing and even becomes friends with one of the guys that molested her. A while ago i found out that its the same mangaka that made honey x honey drops where the main character gets raped multiple times. I guess she has a thing for that.

The characters are pretty good. Some of them are horrible though and others are just kinda funny sometimes, because they do something that would have been OOC but NOPE! I dont know, the characters alright I guess. It works with the story so I don't really have anything to complain about(unless you saw point 2 about Tsubaki acting like nothing happened)

A lot of people are complimenting the art, but honestly, I really hated the way it was drawn. I loved the quality of it however and i could see there went a lot of work into it, but the style in itself i didn't like very much.

Overall, I loved it. Even with all its faults, I enjoyed it a lot. I recommend it, though it's not for everyone. I think the amount of negative reviews says that much. If you wanna read something funny and romantic and are okay with something that is definantly not a 10/10 but would rather focus on enjoyment and put analysis to the side for later, then i definantly recomend Kyou, Koi wo Hajimemasu for you.