Overall speaking the experience of staying here is excellent given its location and the flat proper situation.
The flat is near the metro station , which only takes me 30s to reach it. When it takes to going to Shinjuku station, it only takes 15-20 mins, which is acceptable.
The flat has everything you need, from clean bathroom to small kitchen, there is also a kettle for boiling water.
It would be a perfect place for 2-3 ppl, but I doubt if there is enough space for over 4 ppl.
The environment is quiet, which is super nice because I am travelling with family. there is also a 24h cheap restaurant in case you are hungry in midnight.
I especially appreciate and thank the host hospitality since he was responding very quick and tried to offer as much help as possible.