We had a great stay! The place was spacious for 4 people, and having 2 toilets available is really handy. It's just a short walk from Yahiro Station, with a 7-Eleven and a couple of izakayas nearby. You can take a short walk to see the Arakawa River. The Skytree is visible around the general area.
Ms. Mie was responsive, though we never really needed to contact her because we didn't run into any problems. We did get lost at first, but the map pin was accurate, so it wasn't too much of a hassle.
I would highly recommend it overall!