Very good value. Let me first of say that this is the budget option, so don't expect too much. That being said, I was pleasantly surprised by the value. Note that this was the cheapest place available.
So the room is part of the Carlton hotel in Belgrave Street. It is in the basement (actually the room is under the sidewalk) which you can access from outside directly with a keycard. So you can check-in and explore the city until anytime you like. The room is small but clean. There is a bed, sink, table, small tv, closets, hairdryer, kettle (with tea and coffee) & fresh towels.
The downsides of the room are that the toilet and shower are inside the hotel (and the shower is quite small), but you can access the hotel with the keycard. Also, the mattress was not the most comfortable (it one of those mattresses with metal springs inside). It was ok for me though. And a minor thing was that mobile data signal is weak in the room and you need to pay a small fee for Wifi.
The location is great. Less than 5-minute walk from Victoria station, it has many interesting places within walking distance and access to public transportation. The street was not too busy so noise was not really a problem (for me at least).
If you want a place to stay near Victoria, that is clean, private and inexpensive, this is the place for you. If you are looking for luxery this is not the place for you but expect to pay (a lot) more.