We had a nice 2-nights stay in Stefan's appartement. It's close to the subway-station and it takes you about 30 minutes to get to the center of Vienna. The appartement is big enough for a couple. The only remark I can make is that the kitchen could have been cleaner, the cupboards d fridge had a smell. Toilet, bathroom and bedroom were ok.
Stefan was also very kind to let us leave our luggage in the appartment after our official checkout while we were visiting a museum on our last day in Vienna.