okay, i'll give my opinion... ehe
it has a very clean, cool art style and the music is great. Very euro-pop I think. Everything is very colourful and beautiful to look at.
I watched it in german for some reason, and it's pretty good. Lots of character and believable acting.
As for the plot, you might know that it's all about dreams, collective dreams and all that, so everything is surreal and you might lose track of what reality is in the story, but that's the good part, ne?
As for the characters, I found them likable, but no one I'd put on my favourites list.
Oh... and there's a bit of a fan dis-service, creepy scene, so I'd suggest trying it on your own and not playing it when anyone's small children are around.