Alex and Kate's apartment is better than what you see on the pictures. The flat was spacious enough for our group of 6 and the 2 bathrooms saved our time. The place was clean overall and very tidy. The apartment was fully equipped with appliances, shampoo, hairdryer, coffee, tea (even two umbrellas just in case) etc. There was warm water all day long and the whole flat was very warm due to the central heating. Beds were very comfy and none of my group could find something negative about this flat.
I definitely recommend this flat for a group of friends or families and if I'll go to Prague again I would book again the same place.
City centre is very close, 15-20 mins walk from the astronomical clock square and there is also a tram stop (3 mins walk) and a metro stop (8 mins) close by. There are also lots of local little shops (mini market, pizza restaurant, bar, donuts and fresh juices shop) that were a very nice surprise.