I really enjoyed staying at Tomo's place. It was exactly as advertised, with 3 rooms (2 tatami rooms, and 1 room with 2 twin beds), as well as a dining and living room. One of the tatami rooms is a pretty steep flight of stairs. The location is walking distance from the JR Otsuka station and the Shinn-Otsuka Marunouchi line. The neighborhood itself is a mainly calm and residential, which we appreciated as we were traveling with my boyfriend's family.
The house itself was very quaint. It's mostly hardwood so may be a bit cold for those who aren't accustomed to wearing slippers around the house (we went during the fall/winter). Tomo provided a heater in each of the rooms, as well as additional blankets, so though it was cold outside, we were bundled up at night. One thing to watch out for is potentially tripping the circuit breaker. I think this is common in Japanese houses to not use as much electronics, but we accidentally tripped the circuit a few times (heater on, all the lights, turned on the tv, etc.) so it's best to try to adopt a conservative approach here.
Overall, we enjoyed our stay here and would definitely book Tomo's place again next time we're in Tokyo.