Right off the bat, there's one thing that needs to be said upfront about this series: its main character is a lolicon, and the story is about the line she walks between friendship and infatuation with a 4th grade girl. Most people will probably choose to ignore it based on that sentence alone. But what if I told you that against all odds this manga is a work of art that handles its theme with tact and maturity? Would you reconsider?
I've never read anything quite like Yuzumori-san, but I have to say, I loved every second of it. It's like the inverse of every other romance series I've ever come across. Instead of hoping for their relationship to advance when the "will they or won't they?" moments happen you find yourself on the edge of your seat pleading that the main character will manage to restrain herself from acting upon her lustful urges for this gradeschooler.
You see, Yuzumori-san alternates between two very conflicting but somehow synergistic art styles: the fluffy, flowery way that the series' slice-of-life and romantic moments are drawn, and tense or disturbed panels whenever the main character's carnal desires surface or there is emotional turmoil. Our main character Mimika is acutely aware that her sexual attraction to the young Yuzumori is "wrong". Mimika spends the series agonizingly trying to resist her own deviant urges, trying to protect Yuzumori from herself while still remaining close to her. Chapters can therefore rapidly oscillate between happy, cute and funny moments of the two acting like a normal couple and angst / despair, with a feeling a bit like you've been suddenly thrown into a page of a horror manga. In spite of this, the manga never veers too far into the territory of being tragic or dark and retains the bubbly feeling of your standard slice of life yuri story.
This contrast is pulled off so well that you can find yourself simultaneously disgusted with and rooting for the main character, who is forever struggling to follow her moral compass and maintain a wholesome relationship with Yuzumori in spite of her pedophile nature. And Yuzumori herself, a precocious but lonely child, is loveable in her own right. She deeply cares for Mimika, the guileless way she interacts with the eternally anxious Mimika is hard to hate and the two make for an oddly compelling duo.
My only complaint would be that the series has very little to offer besides the one single plot device of getting Mimika flustered and having her struggle to control herself, there is very little advancement of the story before the last few chapters. But all in all, I'd recommend it to anyone, even if they'd probably give me a disgusted look for doing so.