First off, Peter is a great host. He was very helpful at check-in and great with pre-visit communication. He even helped get my family settled in upon arrival.
The Pros: Apartment is rather large and is in an EXCELLENT location; step outside to the subway, 5 minute walk to St. Stephens cathedral, cross the street and walk the Danube Canal. Plus, it has awesome underground parking included with the rental. There are also numerous bakeries, groceries, and food options within minutes by foot.
The Cons: Apartment, while very clean, is VERY dated. Like 1970s dated. Likewise, the apartment is located in a rather shabby-looking building that I'd probably avoid without knowing otherwise. Apart from the businesses located in the same building, I'm not sure how many other people live there.
Overall: if you're looking for space (think families or groups of 3+) and parking/location are non-negotiable, then you should consider Peter's apartment. If you crave luxury, or something from the current decade, this might not be your venue.