THIS REVIEW IS SPOILER FREE!
What can I say that hasn't already been said about Kodomo no Jikan?
Probably not much.. but I love the characters so much, both the teachers, as well as Kuro, Mimi, and Rin (I love those names as well). I initially started the series out of sheer curiosity, and I got a little worse than I had expected. It kind of felt like the demonic love-child of Toradora and Boku no Pico.
It took me a very long time to complete Kodomo no Jikan even though I had the full first season plus the OVAs readily accessible for at least a month before I completed it. I just couldn't take such high doses of children my baby brother's age being so lewd.. but what got me through the series was the comedy. If I wasn't crying, I was laughing. Not many anime have made me literally laugh out loud more than once or twice. I laughed at least once per episode; sometimes it was because of the absurd situations, or Kuro-chan's elaborate name-calling.
Towards the end of the season, I was loving all the serious background story!
Overall, I really had a love-hate relationship with this series. I still am not entirely sure how I feel about it, but I can say I wouldn't change the fact that I completed it.