I loved Hiiro no Kakera! It was amazing. I was a little uncertain at first but after the first few episodes it really got good.
I'm supposed to tell you why I liked it so I'll do my best.
I really like reverse harems. I said that on my profile, so this is about as reverse harem you can get. The main character is really great. Her personality is real and a lot like me. I would do mostly what she did. (I really hate animes that I want to punch the main character in the face for being stupid.)
The romance in this anime is wonderful. I really mean it, although most of it is in the second season, it is still developing from the beginning. And I gave it a nine in enjoyment only because I selfishly wanted there to be just a little more romance in the first season, because I love it so much, and I thought it was just a tiny bit slow to start. (But I completely understand why they did it.)
The story is very well developed and I loved the twists and turns it takes.
The art was pretty good, some of it you could tell was computer generated, but it couldn't get too much better.
The characters were fun, frustrating, and pretty real. (Which to me is good.)
I hope this review was useful. I tried my best, and if you like reverse harems, romance, (good looking guys), super-natural powers, or all of the above you should definitely watch it. I loved it and I hope you do too.