It was a totally OK stay. But the following details were difficult to name it a 5 star place:
The flat is directly under the roof and there is no AC. On very hot days I wouldn't know how to find sleep, as the windows are very small and don't let in much air.
The roof top is only accessable from the stairs and not directly from the flat.
It's only possible to shower easily for people smaller than 1,60m. With my 1 80m I had to inconvieniently bow. The lavatory is supersmall and it's blocked a bit by a tray additionally.
The mattresses are supersoft, my back complained but to everyone its own.
TV, microwave etc... everything worked perfectly, public transport is nearby, it was clean, the roof top is nice and the price was OK.
So when you're OK with the mentioned constraints it's OK for a couple nights.