We stayed at Ulrike's apartment for two nights, and couldn't have asked for a better stay for our time in Vienna. Her apartment is spacious with tall ceilings and incredibly clean, organized, comfortable and minimally but tastefully decorated. Everything we needed was there, and we were able to do a load of laundry and hang dry it on the rack provided.
We were in Vienna on two of the hottest days of summer, but kept cool by opening up the apartment's big lovely windows at night. Ulrike kindly messaged on the second day to let us know there was a fan in the closet we could use to cool down further. Although we didn't get to meet Ulrike, she was easy to communicate with, friendly, and so helpful with her suggestions and recommendations. Ulrike's dad showed us around the apartment and was very nice as well.
I would not hesistate to stay here again, and would recommend it to anyone visiting Vienna. One of the best we've ever stayed in.