For those who like things to be put in a nutshell: great apartment, good location, amazing host, absolutely recommendable.
For the others, here a few more details: The apartment was very clean and although quite cozy, it's also very spacious due to a smart interior concept (loved the furnitures!). It offers everything you need, even a big closet and a washing machine. The location of the apartment is in the 3rd district and the inner city can be reached easily by taking a walk. The street Landstraßer Hauptstraße is nearby where you can find lots of shops, supermarkets, restaurants, cafés, etc. The neighbourhood is very quite, not much traffic on the small streets. Ralf is an amazing host, a true superhost! He even provided something for next day's breakfast which was highly appreciated. The communation was easy, he always replied very fast being friendly and kind. We absolutely enjoyed our stay at his place which we used as shelter until we found our own apartment. Absolutely everything was great and if you stay in Vienna, take the chance and book Ralf's room, you won't regret it. Thank you for everything, Ralf, it was a great experience staying at yours. Wish you all the best! :)