We stayed at Hotel Japan for 2 nights in peak snow season. The staff were helpful, and the place and a nice musical base ambience. The other guests all seemed friendly and relaxed which was good. One of the music rooms also functions as a locker / baggage change area, which really helped on checkout day.
The hotel also has a semi-separate Nepalese curry restaurant which makes for a good dinner. Parking was good, and since it's about a 5 minute walk from the hotel, the staff will let you park in front for the initial luggage drop off.
The onsen isn't as big as you'd think, but it is clean and seemed in good repair.
The foyer also has an excellent vinyl music collection and turntable, which adds some atmosphere, as well as a library of manga and books to borrow.