We stayed at Chris' apartment for two nights, and it was perfect for us. We would definitely stay again next time we visit Vienna. As in the photos, the furnishings are modern and comfortable. The wifi worked great. There is an underground station right across the street.
Some things to note if you plan to stay here (although none of this was a problem for us): the outside of the building looks run down, but it's clean and the apartment itself is clearly well-maintained. We ran out of hot water one night when we showered consecutively. The headboard of the bed is creaky if you lean against it. The bathroom is quite small, so the sink can be a little in the way when you use the toilet.
Chris is very nice and helpful, and he showed us how to use the Vienna public transport app, and he privided a laminated map of the neighborhood with grocery stores and other shops marked. Overall, we were incredibly pleased with our stay. Thanks for everything, Chris!