This is a good value for the money and if you can figure out the different transportation systems, it is a good location in Tokyo. (If you are planning to just using JR pass it won't be as convenient.) The walk from the station is much further than we expected - it is doable, but if you're traveling with small children or senior citizens it will impact your plans.
We were comfortable with 9 people (four children, four adults, and one grandma).
Our host tried hard to be helpful, and though we had a few set backs, there was nothing that would impact future guests. Oh and definitely make use of the laundromat that is a block away. It cost us 300 JPY for a wash cycle and dryers were 100 JPY for 8 minutes (24 minutes was sufficient for our loads). We purchased laundry soap from the convini next door for 450 JPY.