I finished this series recently. I can't say I find it particularly good but it certainly was interesting. The high point for me was Hoshimaru's empty goggle-eyed stare.
No, seriously, it was ok. The animation was sub-par. I knew that the atmosphere wouldn't stay the same as in the first episode before watching. And while not actually violent the last two episodes it climaxed at provided some very disturbing imagery and themes. Most of the characters were interesting but then the big dismerit of the anime kicks in - that only half of the story of the manga was animated. We never get to know what the dragonets are, why they are there, important character background is left out.
And I have to say that I'm interested too find out what'll happen next and what everything is/was about anyway, so I guess I'll pick up the manga after volume 6.