On all of the four occasions we have dined at Zum Blauen Esel, the service was extremely friendly, helpful and of a very high standard by all of the staff. All of the staff were willing to help with any translations required from the German menu into English. The authentic Austrian cuisine was excellent, it was always flavoursome, well prepared and well presented. They had a blood-orange cocktail on the menu which was divine and very reasonably priced. You were never left hungry as all of the portions were of a good size. It is an authentic, vintage Austrian restaurant with old world charm - this is not a theme restaurant it is a genuine slice of Austrian heritage. It does still have two halves (smoking and non-smoking), we are non-smokers and the non-smoking area did not smell of smoke. We visited at the start of spring and it was quiet and relaxed. We found this restaurant from a recommendation in the Marc Opolo Vienna City Guide; it is very close to the Schönbrunn Palace/zoo and the Heitzing underground station.