A friend and I lived in this apartment for 3 weeks whilst in Vienna and had just the best time. First impressions were great, the apartment was so clean and welcoming and the key system is incredibly convenient, particularly as I arrived quite late at night.
Other aspects about the apartment that we loved was the well stocked kitchen, complete with dishwasher and giant teapot, the decor, the amount of storage, how spacious and light the place was, very effective heating, warm and comfortable beds and the location!!! Tram number one stops right outside and goes around the ring plus you can walk everywhere, closest areas including Karsplatz, the Naschmarkt and Mariahilf.
Plus, the couch in the living room is a proper double bed, which (while exceptionally comfortable as a seat) was really useful for us as we didn't want to share the whole time.
Kiki as a host is very welcoming, made life easy for us by answering all questions we had and being so flexible negotiating leaving and arrival times. Kiki is also VERY prompt at answering emails.
Literally no negative aspects to mention.