I hate to say this because the hotel actually was really nice. Staff was nice, onsen was nice. Room was nice. BUT there were bedbugs in my Tatami room and thus I just have to rate this hotel as poor.
I was seriously eaten up suring the night. When I woke up because of the itches I had bites all over my arms and legs and face! Pretty much any part of my body that wasn't covered with tight clothes. Considereing there were so many bites there must have been a couple of bugs.
Maybe the western style rooms are ok. I think the problem were the tatami mats which are just impossible to keep clean and are a nice refuge for all kinds of critters.
Otherwise the hotel was very nice. Good, central location with partly nice views over the lake. Super nice and helpful ENGLISH speaking staff (I went to about 5 other hotels in Unzen before to inquire about prices and NO one there spoke a word of English! Not even at the super expensive places!).
Prices were good as well. Paid 5400 Yen for one night single room.
Hotel has nice onsen with outdoor rotenburo.
Didn't try the food. Theres a convenience store right across the street which had all I needed for my bugdet traveller's dinner :)