So I've been following the Kaminomi manga for quite a while. However, this review is about the anime and not the manga, so therefore I'll try not to be too biased (and probably fail miserably).
Story - 8/10.
I like the premise for this series. It's original (from what I know) and it's amusing. Despite this, it's quite... hard to explain to people. In a way, it makes no sense unless you actually watch it. It's not complex or anything, but it's just hard to summarise. Or maybe I'm just stupid.
Art - 9/10.
The art style is lovely. I love the colouring. Also, I didn't spot any major QUALITY moments so that's good.
Sound - 10/10.
The music is brilliant. From the theme songs (God only knows is one of my favourite anime openings of 2010) to the BGM to the character songs -- it's all amazing. The voice acting is good, too. The only way they could have improved the voice acting was if they replaced everyone with Wakamoto Norio.
Character - 7/10.
To be honest, several of the characters bored me. I don't like Ayumi's type of character, Elcea is annoying and Shiori is too cliché (gotta agree with Keima on the librarian-type girls here). It wasn't horrible writing or anything, but they just didn't interest me. On the other hand, Keima is AWESOME, as is his mum. I also love Mio. And, in a surprise turn of events, I liked anime!Kanon more than manga!Kanon.
Enjoyment - 9/10.
I looked forward to a new episode every week. I liked pretty much all of them, except for a couple (but you get that with every series so it's okay). I got several laughs out of this series.
Overall - 10/10.
This is one of my favourites. Okay, sure, it's not in my list of favourites, but it's up there. Depending on how season 2 is, it might earn a place. I'm highly anticipating season 2 (is it April yet?), because the next few girls are awesome. Especially Tsukiyo.
tl;dr: Go and watch this. It's totally worth it.