I felt like I was reading a manga in book form. A light novel.
It felt like the author knew her shit, which is always nice. She didn't just read a children's book about Japanese mythology and decide to spin off it so far you could barely recognize it, or you could recognize it, but it seemed so overblown and farcical it causes you physical pain.
It made cultural sense, which was cool. It really was like reading a cross between a yaoi and a shonen manga.
I'm also personally happy she made the nine-tailed fox silver. Partly it's because that's what my childhood impression of nine-tailed foxes are. All of the nine-tailed ones were silver. Of course, a lot of modern interpretations make it red still, but come on. It's nine-tailed.
This, in my opinion, stays true to the mythology/mythological tradition, but still puts its own twist on things. It doesn't seem to blatantly disregard the source myths and still finds room for personal touches. This, unlike many other mythology retellings/reinterpretations I've read of the M/M genre, is good and more importantly, unoffensive. I like it.
I see from the reviews that some people had issues with the Japanese terminology and thought it was inappropriate. The only thing I found weird was that the author never uses the term "kitsune." In a way, though, I thought it seemed like any other manga scanlation I'd read before. I suppose you probably need a bit of knowledge background going in for you to be not jarred by the casual usage of certain Japanese terms?
And no. It's not excessive to have -san or -dono on someone's name all of the time. It's what people do. It's like "Mr." or "Mrs." If you call someone Mr. Brown, you're unlikely to randomly start calling him "Brown." (Best analogy I could come up with; what it does boil down to, though, is marked cultural differences between Western and Eastern cultures, and I feel the author really has a good grasp of Eastern culture).