We booked this apartment at a very reasonable price through Booking.com. The only not-so-good aspect of this apartment is its location. We had some difficulty finding the place upon arrival in Krakow - had to take a bus from the airport to the train station and walk about 15-20 minutes from the station to reach it. The apartment is located along a narrow alley/road, which looks a little dodgy/unsafe at night (although we have never had any problems coming back at night). The train station had a large adjoining shopping mall which had a good variety of shops. Other attractions such as the market square will probably need a tram ride.
However, apart from the location, everything else was simply superb. We arrived quite a bit later than expected, and the manager Joanna was patiently waiting for us even though it was late at night. She was incredibly nice and polite about everything, and did her best to help us with any problems or questions we had. The apartment itself was very well furnished and was very spacious. There were large beds, a dining table, a kitchenette and a well-equipped toilet. Toiletries, towels and hangers were provided as well, and there was free WiFi in the apartment too.
The quality of the apartment is superb and probably unmatched for its price. I would recommend anyone who does not mind walking a slightly longer distance to seriously consider this apartment.