It really is perfect in every way.. Most post apocalypse manga have really heavy dark themes.. That usually turns me off of the genre. But tho this one still have one or two episode of disturbing stuff. It doesn't focus on it that much. The main theme is survival and character adaptation in this environment. The female leads are really tough and strong willed.. Not like your whiny meek girls who always need to be saved. Tho natsu (one of the female characters in team summer b)can get on your nerves the first couple of chapters but then she gets better. The friendship and love lines are pretty solid too. Oh did I mention that most of the male lead are handsome. So overall it really is a great Manga. It contains everything you want and more. You will never be bored.
I read this a few months prior to writing this, but the storyline and details of this post apocalyptic world are astounding. I have my nitpicks, and I really really wish the sexual assaults weren't a recurring thing (only one served any meaning to the plot and characterizations, and even then I think it could have been done differently with the same results. Would have allowed a character redemption, but now he is irredeemable in my opinion.)
The concept really blew a lot of apocalypse stories out of the water, and you had to love following all the characters and seeing how they could contribute or grow, especially our team of mistakes.
In the end, there was this huge opening for us to explore more of the world and get more out of our characters and this story and I'd read any sequel given to me.