The apartment was exactly as described, comfortable, clean, well equipped with all the necessary amenities (fridge, towels, hairdryer, wifi, iron, there was no tv though) and in a quiet neighborhood with easy access to supermarkets. Christian was a great host, very responsive and helpful. The apartment was a bit far from the city centre, but there is easy access to two tram stations that will get you where you want in about 15-20 minutes.
I highly recommend this place to anyone visiting Vienna for a few days!