It is a small, but cosy studio located near Karlsplaz. Considering that the prices in Vienna are quite high, this accommodation is the best you can get while travelling on a budget. S-bahn 1 (tram) is a few steps away from the building and is very well connected with the rest of the city. Also, the neighbourhood is safe, very beautiful (is there anything ugly there?), and it is full of markets and fast-foods. The only inconvenience we encountered was that the closing hour of the supermarkets is around 8pm, therefore be careful to buy what you need earlier or from shops located downtown.
Two things I didn't quite like were, on the one hand that we never met the host in person, but it is just a matter of preference I guess, and on the other hand that the door that separated the toilet from the rest of the room was kinda close to the WC and didn't close very well. Otherwise, Gin was very responsive via WhatsApp and seemed ready to offer his help if needed.
All in all, I would recommend Gin's studio when you travel on a budget.