As much I like post apocalyptic stories this is by far the most awful thing I've ever read in this genre (and maybe manga as a whole).
Mind you, that art is good and the story is okay at first but as the story progresses the plot became an excuse to show off ecchi poses. The characters are either one dimensional or straight up dumb. I don't know what it is even about anymore, I just skimmed the whole thing up to the latest raws just to see if it got better but it didn't.
If you absolutely don't care about the story and just want
to look at anime butts this is for you, otherwise there are other series in this genre that is in leagues ahead of this one.