I don't recommend this hotel to solo traveler who like to keep things practical and don't speak japanese. The big draw for me was the onsen on the rooftop and view. I was looking for something better than the relatively inexpensive hotels i use to stay in while in Japan.
This place is not just than a hotel: it's a huge, self-contained, holiday compound, made of 3 connected buildings, with multiple restaurants, traditional "banquet" areas, karaoke, video game arcade, shops, onsens, swimming pool.. to give an idea about the size, it was a 15mn walk to go from my room to the pool, which is why the hotel has a bus service just to move people from one place to another!
As another reviewer said, it is like a cruise. It is very very crowded, and felt like a club of old japanese people and families, all dressed in yukata, which is nice in many ways, but make you feel a bit out of place. We were really a minority of non-japanese people.
My room was western and japanese at the same time: western beds and bathroom, with a nice tatami room with table, chairs and TV. While the tatami part was really nice, the western part was very dated, straight from the 80s. There is no internet in rooms, not even with ethernet cables. Maybe it will be a selling point someday. You have to go in the lobby to get some wifi.
I have no idea if the onsen is great, simply because the staff didn't let me in, nor did it explained me why. Most of the staff has very little command of english, and the onsen staff has none. This was a big letdown. There was probably a way to solve that, but considering the distances between the buildings, the fact that the staff speaks little english, and that the onsen was probably over-crowded anyway, i decided to abandon the idea altogether.