The flat was very nice and clean. Pictures, as it normally happens, show the space as bigger than what it really is, but considering it's Tokyo, this flat is very spacious!
Decoration: lovely. Cleanliness: spottles! Kitchen has few things but we managed to at least boil eggs, heat up food and boil up water for our baby, etc.
The flat is super silent, so great to sleep. Although not completely dark in the morning, so if you need full black out, just bear in mind you won't get it. We don't care for that as we are used to it. Location-wise, it's not too far from Higashi-Nakano station. However we found the location a bit too far away from everything. This is not the host's fault, it was us not checking well enough where the flat actually was, so we were a bit disappointed finding out that everything we wanted to do was at least 45min to 1h away. But then again, Tokyo is huge, and cherry blossom season makes accomodation crazy expensive, so this flat was reasonably priced and was big enough for what we needed, so it was fine.
Aya was very quick responding everything. Instructions were very clear. The only issue we had was with the front door of the flat, as the keys are not easy to use (at least for us). I would ask before going how to use it. We found it hard to enter the flat several times and were locked inside the flat for some minutes twice. Aya is a very kind host and left nice details for us in the flat, and a list of recommendations of what to do. However when we asked for 2 favours (having a normal chair in the flat, so that our baby could sit with a backrest- as there are only 2 stools there- and having a bit more time for the check out), she was absolutely inflexible. I found that a bit disappointing, however I would still recommend this flat.