We greatly enjoyed our stay at John's apartment on Vladislavova. The apartment was bright and clean. It's on two levels but this was not a problem for us. It's simply furnished. The air conditioning worked well which was important since we were there during a few very hot days. Note that while there is a lift in the building, there are two short flights of stairs that have to be navigated on foot to get to the apartment.
The communication with John was excellent - he responds immediately and is very helpful and clear.
The apartment location is excellent, next to key attractions and the tram/subway. There are also a number of cafes open even late at night so it's very safe.