The apartment is well located, stylish and clean. I've never been into a better equipped airbnb. You'll have everything you need there regardless of how long you'll stay there.
The only minor discomfort was created by the trams running in front of the building which caused a bit of noise and made the building vibrate. However, that's probably common for a lot of other centrally placed buildings in Prague.
All in all I would highly recommend Simona's and Davide's apartment to anyone who is considering it.