Unfortunately, I have to analyse whole anime, not particular parts about it. Why I'm worried? One can say, there are 3 8-episode stories within 1 anime. Overall it's terrible, only first 8 episodes - first story - are worthwhile.
I must admit, I was really interested in the story, and watching first one from these 3 was a pleasure - nice characters with proper background, likeable and realistic. I won't comment on the other two parts, because I couldn't stand nor characters, nor story, so it won't be really fair, but they just lost their uniqueness. It gets worse and worse, so much that I almost didn't complete the anime.
I was truly disappointed - after nice beginning, and well-done first part, the other ones just didn't keep up with it.
So I have one advice for future viewers - stop after first 8 episodes. If the anime ended after them, I would have said, "it was really good".
Sound here is quite good, but not outstanding or catching, although I liked opening.
Art is, to be fair, the only thing that keeps it's good quality throughout whole series, although it's not amazing or anything, just nice to look at.