I can only recommend to stay at Radka's place; the apartment is just big enough - the main living/bed room is big and spacious with lots of light, the kitchen and bathroom are as expected, the place is not noisy.
There are some stairs to reach the apartment, but there is also an elevator to help with that.
The location of the apartment is good too - good area with good connectivity/transit times to other places in Prague.
Finally - Radka was always very nice and she tried to actively help me with any of my additional requests.