There's not much to write about this series that I haven't already written about the first season. But still there are some differences: whereas the first season sets the stage and introduces the 'rules' of the spiritual world that Watanuki has entered through his part-time job at Yuko's store, the second season is more about how Watanuki deals with it. He accepted the job at Yuko's store for a reason, and this time the stories show how he and his two friends (the stoic Domeki and the cheerful Himawari) get into and out of trouble again.
As the apotheosis closes in, the stories get to be more and more intertwined: something that Watanuki gains in one episode plays a pivotal role in another, which gives this season a feel that is a lot less episodic than the first. That's great to watch.
Other than that, much has stayed the same: the character designs, the music, the voice acting, the animation. So if you liked the first season (and there is a lot to like there), you will like the second season even better. I'll give it an 8.