I didn't really expect to enjoy this show as much as I did, and while there were a few things about it wasn't overly impressed with the story was entertaining, compelling and satisfying. It was also quite unique and nearly believable in it's realistic portrayal of possible technology bridging the spiritual and real worlds accidentally. The fact that we aren't too far away from the technology represented in those glasses adds a healthy dose of reality to the show's theme.
At first I wasn't sure if I really liked the characters designs too much, but soon it grew on me and I ended up loving them for their originality and uniqueness. The rest of the show was visually stunning and had a lot of detail to it that I've come to demand of newer shows. This would be what I'd call the measuring stick for 07, it was just that good. It also reminded me many times of Studio Glibi's work.
Rarely do sounds ever wow me but this one's did, and many times over. The sound track and OP/ED were worth spending that extra attention to and for that extra bit I rated it that highly.
Just about everything you could ask for in a character range and development pace. Lots grew beyond their childish limitations, others went even further beyond their traumas and unrealistic expectations of others. There was really only one character that kind of got on my nerves regularly but he was mostly minor and he got a lot of instant karma for it too. I also found it hard to believe that there would be a 17 y/o high school girl working security for a high tech firm as an operative but... it is an anime :P (note this wasn't the main character, most of them are in middle school iirc)
Unique is the word for this show, I'd be hard pressed to really liken this show to another without stretching some thin lines. Which is both sad and amazing at the same time, the show was so very much worth every minute I spent watching it that it seems a pity that there aren't more out there like it, but then that would also detract from what makes it what it is. In any case, I'd be surprised if someone flat out disliked this show since to me this was worth every minute spent on it.