There's a curfew at night and you can only shower during the specified times, but overall it's a decent stay. If you get back past the curfew, you can still get in, but will have to call and wait for the person to come get you.
Bed's a bit hard but relatively comfy. The room we had had 2 bunk beds (4 beds) and a table in addition to locker space. The bunkbeds have curtains around them. The view from the room is nice since it's on the 18/19th floor. It's pretty quiet except for some morning announcements sometimes. I also liked the wifi, but some people had problems staying connected to it. There's also coin laundry/dryer (no detergent so buy your own though). Hot/cold water is available on the 19th floor.
The shower/bath is shared space so if you're uncomfortable getting naked in front of others, bring a towel with you or get one for 200 yen. Shampoo/body wash is provided. If you don't like sharing and want more privacy, you can get a small hotel room of your own elsewhere for less than 1000 yen more.
Iidabashi 飯田橋駅 station (of 4 Tokyo metro lines as well as JR) is right downstairs. There are many shops/restaurants and a supermarket in the same building (on the other side).
