I went on Friday night with a friend to try Blaue Gans. We didn't have a reservation, but only needed to wait half an hour for a seat. The hostess as well as the bartender were quite hospitable.
I ordered the special chestnut soup, which was spectacular. It somehow succeeding being both rich and light at the same time, with a wonderful full-bodied, roasted chestnut flavor. The prune and milk foam was a delightful contrast. For my entree, I had the beef golasch with spaetzle, which was also marvelous. The meat was rich, flavorful, and tender. I am a huge spaetzle fan from my days working at a restaurant where the chef was Hungarian. It didn't disappoint. My friend had the fish special--cod served on a bed of delicious sauerkraut. We both were delighted with the food.
The only sour note was the poor and dismissive service. On multiple occasions, we had to reiterate multiple times what we wanted and tried in vain to get his attention. And never once did he apologize. He spent most of his time chatting with one table, and would bustle past us without even looking at his. We ultimately decided not to order dessert after it took him literally 15 minutes and 3 requests to bring over the dessert menu.
And as a post script, I bought the Viennese hot chocolate and some housemade marshmallows, which I have been thoroughly enjoying as well.