This series brings to mind Harry Potter in both its development and in its set-up, albeit a cutesy Harry Potter with different characters and villians... its own appeals. On the level of plot and setting, it’s deceptively simple and un-complex: you have a bunch of kids in a magic school with a variety of intrigues, from romantic drama to nasty classmates to silly goofs and dangerous adventures. The world is fairly self-contained—you get glimpses and hints of what’s on the outside, and it’s not like they’ve forgotten the world exists—but it takes place mostly inside the school. This is where the resemblance to Harry Potter ends.
As for the characterization and development, you have young characters to start, and they’re clearly very immature in many ways. They’re all variations of stereotypes: the kind, ditzy, naïve girl, the cold genius, the tsundere male lead, the kind-hearted male lead, the irritating “love rival”, and so on. So it’s not their base personalities, but when they break out of these types or when they show how valuable those personality traits of theirs are that you feel touched by them; they all have strong personalities and unique gifts which they must use to struggle and survive in an increasingly dark adult world.
As the series goes on, the story becomes more complex and the tone becomes darker. You begin to get more flashbacks, exposition, and deep, deep drama. (Again, very Harry Potter-like). If you’re someone who read this series within a short time-span or if you’ve reread it, then you probably realized that the darkness was lurking there to begin with: Hotaru’s parents are coerced into sending her to school, Natsume is punished with physical abuse and physical constraints, Narumi’s cheeriness hides a lot of darkness, and so on.
The pace picks up (rather awkwardly) as the manga moves closer to the hundreds (in chapters). It appears to be the final / culminating arc, but this arc has been going on for at least 1/3 of the series now; the mangaka set it up so that things are not going to be easily resolved by beating one bad guy. Most recently she has thrown in a disorienting rapid-fire set of heavy punches plot-wise (non-spoiler tip-off to current readers: the things happening around the time Reo returning), with everyone doing big important things, and to the reader it’s just that feeling—you wish it would end already because you’re shocked and disoriented all the time, but you really can’t even begin to see how it’s going to end and know it’s going to take a while.
My two biggest problems are the current state of the never-ending rapid-fire plot (although all the events and flashbacks are useful, they are nonetheless disorienting) and the pervertedness of some of the stuff. Seriously, I don't think it should be normal for ten-year-olds to grope others, steal panties, and whatnot. But this is a Japanese series, so it'd probably be even odder for NONE of the sort to be there... unfortunately.
A warning to readers of scanlations: a few of the chapters are low-quality translations, and the scanlators have switched around over the years, so you may find variation in terminology (I used to have a lot of trouble keeping the Japanese names of the classes apart) and occasional confusing moments. I never had a problem following the plot and figuring things out from context, though, so I don’t mind this so much.