As every usual manga reader should find out just by watching the first volume's cover, Unbalancex2 is a romance story in all its ecchi glory. Kind of lighthearted (though not always), a bit comical, and having lots of drama and mixed feelings running through. The surprising part in all of this, is that it starts pretty good: its male lead averts the dumbass typical harem comedies protagonist by not getting impressed easily and having the guts to stand up for his beliefs, the female lead is shown as a strong, independent woman who is always in control of each situation, averting both the typical Tsundere and Shrinking Violet
stereotypes. As the series progresses those two strong-willed characters begin opening up to one another, getting unthinkable aspects of their personalities to be known, which is good.
Now, when the series starts taking its downfall is when those aspects start being the predominant behavior for both characters, up to showing them as fragile human beings unaware of how they used to behave. Supporting characters (childhood friends, schoolmates and family members) are there, but seems like the author really didn't make an effort to develop on them, although they had some potential (like Young Gi, Ji Soo, Ami and Carrie). They weren't absolutely out of the picture, but they definitelly fell flat on the supporting character category, which they never left.
As far as I know, the Author had something bigger in mind, but it horribly backfired on him by teacher-student relationships being a taboo topic in Korea, so maybe he didn't want to ellaborate to avoid getting in trouble. And that's really Unbalance's biggest downside: its inhability to go further although it had a strong, interesting topic to ellaborate on. The Japanese release is intended to include some dialogues and scenes left out in the korean release, so that's probably the edition to look out for in order to get a more complete story.
Overall, Unbalancex2 is not bad per se, just didn't stood out for itself even when it had everything to do it. Drawings are great, dialogues are not bad, but the story just hit the Average floor hard by not developing its characters and the relationships between them. I would recommend it anyway, since it's an entertaining and lighthearted reading, and that's what it's all about. Beware the final part though, since it's a lot darker.