If i am ever going to Tokyo again i will try to get this flat again!
Our stay at Sayoko's place was just great.
You got 2 Stations within 10 minutes walking distance(i think to get to Asakusa in the north took us barely 30 to 40 minutes from the flat), some little convenience stores are really close by and a whole shopping street starts 100 meters from the flat.
The flat was clean, not noisy and the bed was comfortable. (Oh and there were snacks and something to drink when we arrived. Thanks for that Sayoko)
The best thing is that the flat is right on top of Sayoko's shop. So in our case if we ever had any questions or needed any help she was right there.
Overall i can only say Sayoko is a really nice person and the flat is...well it's simply a great flat.