1 star seems like a harsh rating for this and I'm kind of hesitating between 1 and 2 stars, but, in the end, I was simply very disappointed with this book and even though it is not horrible, I "didn't like it".
Sidonia is a post-apocalyptic story, in which humans fight for their survival against aliens. This is nothing too special or creative, but could always be an entertaining story. However, nothing quite worked for me in this book.
First of all, there's the fanservice. The series starts with the male main character running into the equivalent of a female changing room. Later on, you get an officially androgynous but basically looking like a flat-chested girl character who manages to jump in a way that the main character's head ends up between his/her legs, as well as girls with expressions that look like arousal when using urinary catheters. Uhm, no, thank you.
Fanservice like this is something you unfortunately (imho) see in every second manga, but it really doesn't fit the serious tone of Sidonia.
More importantly, the characters, who could make me overlook such things, are not intriguing in any way. They're boring. And from the way Kunato acts in this volume, it seems that there will even be some kind of teenie-mobbing of the talented newcomer by the jealous popular guy or something similar.
The series is also quite violent and has some pretty gory images, which doesn't help my non-enjoyment. I also don't care for mechas in my SciFi series, they look ridiculous.
Nihei's works always look good. His backgrounds evoke a dark and depressing atmosphere and there are lots of details. However, the characters' facial expressions are always kind of "void". I guess this is mostly because their eyebrows never move, and eyebrows play quite a big role in letting our expression convey our emotions. It looks very weird to have a character who is surprised with his mouth wide open while his eyebrows stay as the perfect arcs of a neutral expression.
I've tried some of the authors other works and I didn't really get into them either. Somehow, they just seem to be lacking something to get me attached to the characters and/or interested in the story. Sidonia is shiny on the outside, but for me, there are no emotions on the inside.
I suppose that Nihei's work simply isn't to my taste. Other people might very well enjoy them. Especially if you like dark and violent SciFi and don't mind the fanservice, you could give this a try.