We've had a wonderful stay in Vienna, largely thanks to the Khawam. George was waiting for us in the apartment the day we arrived. He showed us everything and didn't leave until he had made sure we didn't need anything else. He also insisted that we should call him if we needed something.
The apartment is just perfect, amazingly clean and tidy. It is five minutes walk from the UN and three minutes walk from the metro station from which you can go downtown. The neighbourhood is very quiet and has everything you need: supermarket, restaurants, a bank, etcetera.
In conclusion, we'll definitely go back next time in Vienna!