The appartment was perfect for me, maybe even a little too spacious for a single person. Probably best for two, since I didn't really need to use the living room. All is as described by the host, check-in and check-out is incredibly easy and straightforward and there were no problems during my stay. If you are a light sleeper, you have to take into consideration that the appartment is located in an area that is busy day and night, so you will likely hear people on the streets even at 3.00 a.m.
The advantage of the very central location is that you can reach almost all of the major sights in the city on foot. So in total I was very happy with my stay.