I haven't stayed at the Ueno property, but I have stayed at another Mitsui Garden property. IMO, they are a rung up from the run of the mill business hotels because... Their bathrooms are tiled, not one piece molded plastic unit bath. The room photos on MGH Ueno shows it.

It may seem trivial, but there's a saying that you can tell how much a hotel has spent on a guest room by looking at the bathroom fixtures.