Pros: This place is adorable! It's very clean and the efficient use of space was charming and ensured we had everything we needed! Check-in was easy, the third party leasing company was very responsive and easy to work with, and downstairs there is an amazing bakery (Haruka Breads) where we had breakfast every morning!
Cons: The noise of traffic was quite loud. I've stayed at four different AirBNBs in Japan over the past year and never has it sounded like the door to the street was wide open. I got used to it a few nights in, but sensitive sleepers might want earplugs. The location was 5min from a non-JR train station, but as tourists in Tokyo, we ended up having to transfer from that station to Shinjuku Station for the Yamanote Line every day. That adds up in cost and time over the course of a week.
Not a con (we liked it), but more of a warning: the apartment is probably about 150 sqft or less, so we wouldn't recommend more than two best friends staying here. :)