Stayed 2 nights with daughter, 11yo a month ago. We found the room large enough after storing the large suitcase just under the coat hangers. Definite improvement over Ibis properties in Osaka.
This property is not going to be a Mercure for long, it is a cool boutique hotel whereas every other Mercury I stayed at has been a budget hotel like Ibis.
I could not recommend this property higher than OP it is just really good, especially the Avocado breakfast sandwich. Name me another Mercure where you get one?