There are good and bad things to say about this place.
The communication with Alex was great, and he responded quickly. We requested an early check out with was immediately arranged. Unfortunately, it seems there was a misunderstanding with the cleaning person. As we dropped off our luggage the cleaning staff immediately left before their work was done. There was dirty laundry in the machine, the fridge was full of stuff from previous people, the grill was dirty and overall it didn't look thoroughly clean, in addition, the glasses in the cupboards were all dirty and sticky as well as a lot of empty bottle and recycling was stocked in the kitchen. This definitely ruined our vacation mood, since we had to clean it ourselves and that's not what we paid for. Other than that the apartment is in a great location and the rooftop terrace is amazing. Some furniture was broken when we arrived (chair), and generally, it looks very used and a little run down. It seems like the owner doesn't invest much in the place and it shows.
Personally, for this price, I would rather stay in a hotel with a rooftop terrace (there are many in Zürich).