The double (single use) room that I had was tiny-- I barely had room to open one of my suitcases on the floor. Underneath the bed and behind the desk looked like they've never been cleaned, but the actual top of both were comfortably clean when I checked in. The bathroom came with liquid bath soap and shampoo, which was great, although the dispensers had them caked onto the bottom, which was kind of gross. The bidet remote's chain was broken, but it worked fine.
The area in Shinjuku (and near Kabukicho) has sirens and accompanying loudspeaker announcements until 2 or 3 in the morning some days of the week, and the room was not soundproof from the outdoors. On the other hand, I didn't have any issues with noise from neighboring rooms in the same building.
The internet worked well. Guests (who aren't signed up for the room) aren't technically allowed, but the staff didn't seem to enforce it strictly, despite the signage. There's no non-emergency staircase, so you'll have to wait for the elevator every time you come or go. I'd recommend this place if you're on a budget and you want convenient access to Tokyo.