Space could be bigger, but it's not too bad. Bigger than some hotels I've stayed.
The stairs leading up to the stays is quite cramped. Will not recommend if you're carrying a large suitcase, or are unable to carry one up flights of stairs by yourselves. If you're westerner or someone with a bigger build, you might have some problems carrying your luggage up.
It's about 5 minutes away from the nearest station, which isn't too bad. But the path leading to it can be confusing, but nothing too difficult. It is quite a distance away from the main areas of Tokyo, so just make sure you do your homework.
The hosts are... the worst I've dealt with. I was a lot more polite than they were, and honestly, they made me feel quite unwelcomed with the tone of their messages. Their responses were very curt and lacked any warmth. It's as if we were imposing on them by renting their apartment (they are not staying in the same apartment).
We had a bit of trouble unlocking the door, and had to contact the host. They were on their way here, said will be here in 5 minutes. After 2-3 minutes, we figured it out and managed to unlock the door. But it was a bit off putting to realise they were just minutes away (assuming they were already OTW to us), but they did not even want to make the effort to meet us in person to make sure everything was okay.
I've stayed in rural places where the water heating system functioned better than theirs. It sometimes take 5 minutes to get the water heated, so you have to turn on the faucet way ahead of time (which is a waste of water). We came during the winter time so we had to wait for the water to heat up. But sometimes, the water becomes way too hot. So you have to mess with the faucets again, and then it becomes icy cold... and it starts all over again. Sometimes the water flow also reduces by itself. We have absolutely no idea what was going on with their water heating.