In my own experience, the service and hospitality of Japanese people are second to none in this world !!
I stayed at Seiryuso a few years ago in southern Izu. Although staffs barely speak any English (we understand a little Japanese), the service there to me is better than any FS or Aman I've been.
The friendly staffs there treat you like family, and they really go out of their way to make sure we get everything we need, even when we didn't really share common language, it was just amazing
I've never stayed at Murata, but know several people who did, but heard lots of positive comments. Murata is one of the most famous ryokans in Japan too.