Don't let the cute visuals fool you, behind this lies a comedy that can be pretty dark and effed up at times, but brilliantly so (here is a pretty good example from episode 1 which is by no means the only effed up thing in that episode ;) http://www.youtube.com/watch?v=42u4ytkzAWw). The story is anything but standard as well, this is a strange world where we are told that humans are dying out and the fairies are the new dominant species on the planet. Our nameless heroine serves as the mediator between humanity and the fairies, which as you might expect, gets her into many bizarre situations.
One of the things I really like about the series is that behind the cute visuals is a setting that is actually pretty dark. Humanity is dying out, and the fairies may look cute, but they are also rather creepy and respond rather strangely to human interaction. It's hard to know what they actually think of humans, and I at least got the impression that when humanity eventually does die out, they probably won't care or even notice.
I love our heroine in this story. Sure, she's cute like almost every girl in every anime, but she also possesses a dry/deadpan sense of humour which you see regularly when she is confronted with yet another bizarre situation. I found her very charming and it made it all the more enjoyable following her through this bizarre post-apocalyptic (kind of) world.
If you want something a bit quirky and different from your standard harem-anime-in-a-school fare, I'd definitely recommend this one. The series was written by Romeo Tanaka who has previously written some great Visual Novels (my favourite being Cross Channel). If you're familiar with his works then you might go into this knowing what to expect. Hopefully we will get to see more mainstream anime series by him in the future!