I'd definitely recommend staying in Martina's place because it's the perfect base for exploring Prague! The apartment was exceptionally clean and very spacious. There was even a room between the main room and the bathroom that had big wardrobes that you could fit all your things in. The kitchen was fully equipped, although we are out all the time because there are great restaurants within walking distance.
The location is absolutely perfect. We could walk to anywhere we wanted to go, including all the sights, restaurants and bars. Despite being close to everything, the building is quiet, and you don't get noise from bars or anything. It was also easy getting from the airport to the apartment with public transport, and Martina provided great directions.
Martina is a fantastic host who really went above and beyond to make our stay as easy as possible.