We had a great time at the Writer's Flat. Checkin was easy and everything was according expectations. The apartment was also very clean. Whenever we had questions we got a prompt response. We did not use it (too many nice restaurants) but the kitchen seems well equipped also.
The apartment we had was on the first floor so we did not have any issues with stairs like some other people mentioned.
Apartment has airco in all rooms but we did not need it. Opening the windows at the end of the day was enough to cool down. When we were there temperature outside was around 26 degrees so maybe you need them when it is warmer.
The location is good. Many restaurants are nearby and you are close to the river (5 min walk) which is nice to go to in the evening.
Thing to keep in mind is that the apartment is above a restaurant which is open until quite late (~ 1:00) and the music is a bit loud during that time. If you are a light sleeper bring some earplugs. The restaurant was open 4 nights a week when we were there. Because we walked a lot during the day sleeping was not an issue for us :-)