We had a great 3-night stay. It was the perfect base to explore the city, and to easily get to and from the start line of the Valencia marathon(!), with several metro stations within a short walking distance.
The apartment is on the 4th or 5th floor, so be prepared to walk up 93 stairs. The benefit of it being so high up is that the apartment is quiet and you can hear only minimal noise from the street below (said as someone who is a light sleeper).
The bed is firm but comfy (felt like memory foam).
The shower design is a bit silly (as others have mentioned) but it is fine to use and the water was always hot.
Great contact in advance of our stay to make sure we knew where we were going, and really helpful info contained in the guest book.
Would definitely stay again / recommend to others, especially when the apartment was reasonably priced compared to lots of other listings that had inflated their prices for the marathon weekend.