Mai is extremely hospitable. We got lost and she stayed up until midnight for us to arrive and invited us for a beer in her cafe. Mai and her husband made us feel very welcome, but we also had complete privacy. We stayed for 11 nights.
Mai also told us local tips about events and places to visit (we particularly liked Nakano Broadway).
Shimo-Kitazawa is busy and has a great night life. There are many used clothing stores. Mai's house is right next to the train station, which made it very easy to explore Tokyo.
I recommend trying the grill place to the right (facing the fence) for dinner.