Great location, situated right outside one of the exits of Komagome station on the Yamanote Line (which runs in a loop). Yet like the other reviews stated, there is hardly any noise from the trains and it is very quiet. There is a convenience store downstairs and a good selection of Japanese food around the area, which I believe is an affluent suburb neighborhood. In the vicinity, there is a supermarket (Maruetsu Petit), a 7-11 / Seven I and a few other convenience stores. Go explore the area; it's pretty nice.
Shared amenities - there is a washing machine and drier in the same room at L4 iirc and a microwave at L7 - which makes it very convenient if you buy a meal off one of the convenience stores nearby and need to heat it up.
The room - I believe it is bigger than average for Tokyo standards, fairly ok for 1 person. There is a long desk beside the bed, great for putting your stuff. Heater and AC both available. The toilet is an awesome Japanese one - with heated seat (if you wish) and water spray to clean up after you take a dump.
Breakfast - there is a restaurant at L2. If you choose it during the booking, you will receive cards during check in, one card per day. The selection is pretty limited, but you can easily eat off a convenience store in Japan and there are other food options nearby, so fret not.
Staff - some of them speak some English. Do not expect an unrealistic level of service as this is a basic business hotel - that said, the staff are polite.