My partner and I spent three nights here for the festival, and it's a clean student accommodation.
The good thing is the reception is 24 hours, and the room is clean. Also, it's a walking distance to the most sightseeing spots in Edinburgh.
However, the twin bed is difficult for two adults even though I am small. The window is not easy to open, so it's a bit warm in summer. There is no soundproofing in the room, so that you can hear a lot of noise from people slamming the doors all night and in the morning. Finally, maybe we didn't notice any reminders to bring your own towels as they charge £3 per one. And they charge £10 for keeping a suitcase. Also, when we checked in, the late checkout with paying an additional fee was fine; however, while we applied the day before, they changed their policy again, saying they needed time to clean the room. The checkout time is 10 am, which is a little bit earlier.
It's more like a better hostel, allowing you to have your own space. But please do not expect it to be a proper hotel.