I think this anime is kind of unique, with mini sized human live as theme, makes me very interested to watch it and leave a deep feeling of it. The shades of fantasy is so strong but not exaggerate.
Story: It a simple one, with fine pace, without any boring scene. Ending is almost perfect.
Art & Sound are so-so, I like the background art of it, I don't really have any comment except that.
Characters: the design was fine, either with their personality, seiyu voice are suited well.
Enjoyment: I think Karigurashi no Arrietty will be enjoyable by anyone, although they're not an anime fan. As I mentioned it before, it leave a deep feeling for me, so for me it feels like there's not enough if watch it just one time, makes me want to rewatch it again.