This is an awesome classic and I am a fan forever. Well, I'll admit it: I've actually mostly just watched the anime. From what I've read of the actual manga, the anime was really faithful and works well with the main characters, who are very, well, animated. They're energetic people with fascinatingly morphing facial expressions who chew the scenery like crazy, and a format with movement really shows them off amazingly well. Also the theme song for the first season is really fun, energetic and bouncy. So really, if you're going to read this, IMO consider watching the anime instead or as well. This is probably the only manga I've ever said this about.
But anyway, in whatever format, this is a massive classic. There is an arc or two I don't really like, and I could quibble with a couple more things. But I don't feel like it because I love Risa and Otani and I love the storytelling. The dialogue is snappy, the comedy is hilarious, the characters ooze charm. And . . . look, shoujo romance always has the basic difficulty, "Why this guy?" (heh. So does real life I guess) It has to convey to you this feeling that it's right for this girl to fall for this guy, has to give the chemistry. And a whole lot of the time, it all ends up hanging on an incident or two where the guy shows that he's awesome or cool or nice in some way. It can work, but in real life most of the time that's not what happens, right? And in real life very often someone might do something nice but you don't actually have a ton in common with them so you don't fall for them you just think, "That was a nice thing that person did" and move on. What I love about Risa and Otani is that they fall in love because ultimately they have little choice--their chemistry overflows the page, and nobody else can keep up with their pace. Some of the early bits where they plot together to get the good-looking significant other they're trying for to go to the beach or whatever with their group of friends so they can flirt with those people, but then once they're there they totally have so much fun together that they don't notice that they forgot to try for that other person until it's too late--classic. And despite, sometimes directly alongside, the comedy, the feelings are often strong and deep. The scene about "bear curry" had me laughing and blinking back tears at the same time.
It probably doesn't look as impressive now, but at the time this came out I remember most of shoujo being pretty . . . samey. It wasn't as genre-aware as it often is now, and really you had a lot of the same kind of wistful heroine with the same love complications and plot curves. Not that I disliked it . . . I'm a sucker for those doki-doki feelings and shoujo could always be counted on for that. But still, it was I think ripe for a bit of a shake-up, and this I think was one of the key manga that started to deliver that shake-up, and really stood out at the time for quite different characters and strong characterization and generally playing with the formula. I suspect Love-Com was influential and part of what brought us to where we are now, where shoujo is still writing in many ways the same basic situations (after all, romance about the lives of young people only has so much realistic room to operate in), but with a much broader variety of characterization, tone, and approach to plotting within those situations. Love-Com may not stick out of the modern field as much because of that. But it's still very very funny.