Yuka's place is a great place for an authentic Tokyo experience! The area is great (only a 5 min walk to the station and lots of 24/7 convenient stores near by), and it was only a 30 min train journey to most of the tourist areas (including changing train lines)
While it is small, my husband and I found it was enough space for us. We didn't feel cramped and it was actually very open and bright, especially in the day with the windows and curtains open. Just go with the expectation of it being small and cosy, and you will be fine! I will say though, the shower was a bit small for me and I struggled to wash my hair without knocking my elbows on the wall - but my husband didn't mind it at all.
Overall it was a great accommodation for us, and we were happy with our choice. It's well stocked with necessities like toilet paper, soap, shampoo, washing detergents etc and the bed is comfy. I found the Zens team to be very helpful and they always replied within 5 mins (even when I messaged at 11pm one night with concerns about a typhoon - they replied soon after with information about safety procedures).
Thanks Yuka and Zens team for a great stay!
P.S. If you stay, I recommend the bakery down stairs for breakfast!