Echoing other reviewers about the strangeness of a hotel room without a single window. Waking up in a pitch black room is disorienting, especially when you travel and are a bit jet lagged and you can't really tell if it's day time already when you open your eyes. 2 other friends got rooms with windows, albeit very tiny ones.
It's also not very convenient to access from the street (flight of stairs a bit far from the front door, cabs can't drop you off at the door). Basically this was not built to be a hotel; it's a building the owners of the bigger S31 Hotel had in their possession and decided to turn into a hotel, explaining some of the shortcomings.
Otherwise it's a pretty good hotel with a nice and friendly staff. The breakfast included is decent.
The location is convenient (close to BTS) but it is located in the "Japanese red light district" so you have to pass by a few bars with scantily clad girls hanging out at the front door.
Half of the place is also under construction (adding windows?) so there is banging going on early in the morning (October 2012).
As others have said, good hotel for singles or couples, not so much with family.More