Well, this is a must visit place in Vienna. Nice modern food. Out of 'tourist goulash/apfelshtrudel/mozart eggs'. Good wine, juicy food, it makes me feel being in a meaningful place + good coffee
They're pretty full on Sundays so do make a reservations. They do try to help you to a table when they're full up but you have to leave before the reservations for the table arrive.
There are not so many guests at the terrace, however, it took 50 minutes and an argument with a waitress to get a simple cappuccino. And still they forgot to bring a glass of water. Unbelievable.