Sladan was a great host! I arrived at midnight, and he helped me with my excessive baggage. The room was ready with a set of towels and Manner wafers! There are tourism flyers available nearby the door.
The apartment was only 3-5 minutes walk to Messe Prater subway station and, in my particular case, the Messe Wien which hosted the conference I was attending.
In short, I had a comfortable stay and great time. Danke schön, Sladan!