I honestly wasn't expecting that much from this show - people who summon robot-looking 'dolls' to fight each other? Yeah, I haven't seen /that/ 100 times before.
But I gave it a shot because I was bored and looking for something to watch and I have to say, I'm impressed so far. The tone is a lot darker than I was expecting, it isn't afraid to get bloody, and the characters are pretty decent. Though I have to say, the main guy (whose name escapes me at the moment) actually seems entirely ancillary to the plot at this point. Hopefully he will do something other than run around being worried/angry at some point so I can care about him a little more.
Utao-chan is the new holder of the 'cutest anime character ever award', though.
I also really, really like this show's OP. Not the song so much (although that is decent), but the animation. It's pretty visually interesting, and a lot more unique than the typical 'let's fly around in big swooping shots while the music plays' sort of thing. I've gone back and watched it several times just on its own.
Hopefully this show continues to prove itself interesting as it goes along.
Winter seasons seem to be the best recently.