Excellent location. City center is walkable (few 100m). Tram stop is just in front and metro station few 100m away. We enjoyed the illuminated buildings late at night till 2 am without worrying about transport, because it's just walkable.
Room is very big, tall ceiling and well ventilated. Typical posh Austrian apartment.
Marcus is very good at communication. He arranged the keys with his friends as we got delayed.
Over all for exploring city, it's a very good place to stay.