High Class Viennese
Why locals love it
More expensive but great Viennese and Austrian food in general. Staff is a little unfriendly and pushy though. The restaurant is basically full all the time, lots of musicians drop by (the concert hall "Konzerthaus" is located across the street). Good local food and wine.
Why you should visit it
If you want to taste the better side of Austrian cuisine, that's a good place to start. Especially in the evenings. Bring enough money and a little nerve for the waiters. If you decide to sit outside, be sure to not be too loud after 10PM (welcome to Vienna). Not for vegetarians.
Tafelspitz (Beef, slowly steamed)