Sakurai is one of the biggest hotel in kusatsu onsen. However their public bath uses 100%fresh onsen water from two different types of hot springs. One is a clear water, the other ones are white water. They're both great.
I visit this ryokan annually with my family. My kid has severe food allergies (dairy, wheat, egg, nuts, sesame) but they always make special meal for my kid. Staff are very kind. You can choose table service dinner or buffet. I've been both, and they were both great. They make buffet dish fresh, not frozen meal. Some are with chef's station (sushi, steak grill, tempura etc).
From 730pm they have a Japanese Taiko drum show and dance. From 8, yumomi experience show. If you join the performance, you get ¥500 ($6) voucher for a souvenir shop.
Very relaxing ryokan. Most rooms are renovated and nice. Easy walk to yubatake but they offer free shuttle from the hotel too. Very recommended!!