The number one reason why I watched this show is the simple & clear Japanese language.
Except for the business talk, I almost did not have to rely on the subtitles.
As an intermediate Japanese learner, it was pretty rewarding.

That's actually the only reason.
The story can be summed up into: "They should not be together. Will their love triumph?".
The reason why "they should not be together" is quite silly. It doesn't make sense, even considering the supernatural aspect.

In conclusion, it's a good study tool, but a pretty average drama.