I'm putting this down as an "arc" review, because despite my best efforts, I gave up on this show after suffering through seven episodes.
First, the good things:
The animation is done very well, and the world in which the story takes place is very large and fleshed-out.
Now, the bad:
Every single character is boring and uninspired as hell, and I couldn't bring myself to care about what happened to any of them. Nobody acts in anything close to a reasonable way, and all plot twists are seen coming several episodes away. For instance, the main character is betrayed by one of her "friends" within a few episodes of starting. You see this coming from practically the first episode, since this friend's SINGLE displayed characteristic is that she's some sort of narcissistic sociopath, and once they end up in the world the series takes place in, she's convinced that she's supposed to be some sort of "chosen one." Why? Who knows? Nobody even MENTIONED a chosen one in the story.
Even the main character HERSELF is two-dimensional. Here's everything you need to know about this character: 1) She has red hair, which makes her something of an outsider. 2) She's insecure and thinks people don't really like her. THAT'S IT. For instance, some weird monkey-looking guy keeps appearing to her when she's alone, usually insinuating things along the lines of "people are glad that you're gone," "they're using you for their own ends/are going to betray you," "you're not a good person," etc, etc. Does she question who this guy is and what his motivations are? NOPE! She plunges into self-doubt and self-loathing that would make Shinji Ikari tell her to quit bitching. The ease with which the monkey-guy manipulates Youko is ludicrous, and it isn't until episode seven that she actually tries to resist him, in the only bit of character development I've seen ANYWHERE in the series.
VERDICT: SKIP THIS SHOW.