We stayed with our 4 year old twins and were only a couple of minor issues with our stay - the host was late for check in and the wifi was slow. Apart from that, we were really impressed with this place.
The location is amazing - right next to Powder Tower - and although you have to climb three storeys without a lift, once you open the door to the apartment, it feels like home. It's super clean everywhere, and the sheets are like at a hotel, fresh and white. The kitchen, the bathroom and the toilet are brand new and sparkling clean. There is soap everywhere and towels for everyone. Communication was great.
We'd definitely recommend this place in Prague.