This is a nice looking small apartment (probably not so small by Tokyo standards), stocked with everything you need for your stay. The locations in relation to 2 different stations, a nice 7-11, laundromat, and grocery stores is superb. The host, June, is very quick to communicate and help with anything you need. Overall I think this will be a great option for most travelers.
I'm sensitive to sound, so this next bit probably won't matter to you so much-- but I found there was a lot of noise, particularly late at night, from three sources; the air conditioning system can be quite loud, and some guests above me would have it revving up in starts throughout the night-- sometimes sounded like an old truck engine starting outside the window; then there was a neighbor who sits outside late talking on the phone right outside the window (not every night, but several, and sometimes until 12 or 1am). Then there's the ceiling being rather thin, and guests rudely stomping their feet (depends on the guests), which creates the effect of feeling you're inside a large drum (god forbid loud-talking guests). I know these things might be kind of common in Japan, but I'm sharing the experience people like me who have trouble with these kinds of annoyances. And yes, in all of these cases I used good ear plugs and still had trouble getting to sleep most nights.