We enjoyed our stay at Sasa's. He is a kind and cool guy who not only helped us a lot and made sure we were settled and comfortable, but also had a nice conversation with. The apartment is perfect. We were 4 adults + dog and had a very nice sleep, it could easily fit 5 or 6 people due to a sofa bed I the living room area. The location is perfect! Walking distance to Mala Strana neighborhood (Charles bridge). There's supermarkets and restaurants nearby and the place itself is very clean. Three things to note (which is no problem at all) are: 1) if 4 people have to shower 1 after another, it may take time since the boiler is small and takes time to re-heat. 2) Washing machine seems not to work (does not centrifuge the water very well). Of course, Sasa told us about this so we know he'll get it fixed soon. 3) Apartment is located in a 4th floor without lift. For us it wasn't an issue, but not recommend for elderly people or if you have to carry a lot of luggage.
Thanks a lot Sasa, we hope to see you soon.