Marina's apartment is a perfect base for exploring Vienna. It is located in the heart of the stylish 7th district (Neubau), surrounded by quaint streets with great restaurants, cafes, and stores. Walking into the historic 1st district is very easy and takes about ten minutes. The U2 and U3 metro lines can be accessed with short walks. The apartment itself is a fantastic balance between an old Viennese style building, and a modern and fresh interior. I was pleasantly surprised by the size of the apartment, especially the bathroom, as most other Vienna apartments I've stayed in have quite small bathrooms.
The only negatives I can report are minor ones. There were no toiletries when I arrived, and the bathroom could use some basic accessories. Also, the apartment lacks a desk or any surface with a height that's suitable for working, which could be a problem if you intend to do work while there.
But all in all, Marina's apartment is terrific, and she responded very fast to all my messages. I highly recommend her apartment to anyone visiting Vienna.