Hiroyuki´s place is truly unique, and as all unique places has pros and cons and might not suit everybody´s need.
PROS:
> the location: this Tokyo area is truly a gem, full of things to do and discover and everything is at walking distance from Hiroyuki´s apartment;
> you are in a Sento: you can take the bath as many times as you want. We didn´t get the chance to try it ourselves, as it was difficult with our small son and my husband´s schedule; however the sento looked nice and I´m sure we would have enjoyed it;
> the beds: are really comfortable and the bedsheets are fancy
> Hiroyuki´s instructions: he provided us with detailed instructions to get to the place, which is much appreciated when you travel in Japan
CONS:
> there is no kitchen: a fridge and a microwave are provided, however they are on different floors so you end up running up and down if/when you forget something. Two cups and two glasses are provided, but there´s no dish soap to wash them with after use;
> you are in a Sento: you don´t have to pass through the Sento to get home, however the sento is with you at home: the house is made of wood and every sound of the sento is resonating through it. Since the bath is mostly something Japanese do in the evening you have a lot of noise up until very late (one night it was until 2am). If you are a young couple and you´re going out this shouldn´t be a problem; this wasn´t our case sadly.
I think Hiroyuki´s place should be considered like a huge hotel suite, so if you know you won't need all the facilities of an apartment it will suit you. And bring ear plugs :)