The Rex is a bit like a cleaner hostel with the option to have your own bathroom. But, what's important to note, is that the sheets and towels were all clean, the shower had good pressure and hot water, the bathroom was clean, and the air conditioning worked. They even give you extra pillows from the outset.
That said, the walls are stained and full of nail holes, the furniture damaged, and the room very small. But you're also paying a third of what you would at a normal hotel. And the location is on point.
If you just need a bed and a shower because you'll be out all night having fun anyways, I say go for it. I would stay there again. Why pay more for aesthetics?