Kumina's place is lovely! The home is very clean and spacious for 1 person and is big enough for 2.
There is space for your luggage, but maybe no more than 2 full sized luggage if you have 2 people. For me as a solo traveler, the space was perfect! The bathroom is quite spacious too.
The Sakurashimmachi/Setagaya area is wonderful, I sort of fell in love with it. Quiet but still convenient. I was a bit worried about the 10 minute walk to the station, but it really turned out to be a non issue. I actually really enjoyed the walk! There's lots of food places around and 2 or 3 Family Marts on your way to and from the station. The train ride into Shibuya is only maybe 10 minutes? From there you can get anywhere quickly as Shibuya is a major hub for all other areas.
Overall, I HIGHLY recommend Kumina's homes! For me perosnally, I don't really have any negatives to report. Amazing host, lovely homes and convenient. Check in and check out process is super easy as well. There's even pocket wifi provided, a major plus! I will be booking again on my next stay in Tokyo. :)