I haven't watched the anime, but even still I'm disappointed.
I honestly loved this series, until the very end. I liked the characters and loved the art. I did like the "twist" (I guess you could call it that) at the very end, but it seems like the other half of the story was chopped off. I even looked online, hoping there were more volumes, but no. This series had a 3 volume adaptation and that's all. It's kind of a slap in the face, especially if you got your hands on the physical volumes. They're extremely expensive and they're cheating you out of a great story.
I loved what I read, but it leaves on a cliffhanger and says, "screw you, watch the anime because I have nothing else to offer." Guess I need to watch the anime now, but I'm going to have a bad taste in my mouth after the manga, which is a shame.