Here's the back of the furnished house. I still have to get the dining room and nursery. There is an additional floor available from direct service which could be added to give more room for the existing furniture or add more. I would probably add an office and an additional adults bedroom. Lighting sets are sold for each floor. I think priority would be to get the lights for the ground floor with less need for lighting on the top floor.
It's a nice house with some lovely detailed room sets, but it doesn't seem as solid as the house it replaces and I would have liked to see proper dividing walls between the rooms. My favourite room sets are the living room and adult's bedroom, mainly because of the fire effect and working bedside lights.
Buy one, you know you want to.