I organized a work meeting for about 20 people in Essen, and this was one of the places we went to. We had two children with us. We made reservations at this restaurant, and were given our own room and the opportunity to select a set-price self-service 'bar' (unlimited drinks, we all opted for the wine/beer option, which was slightly more expensive).
The owner aims to have a restaurant offering reasonable prices and a cozy atmosphere. It certainly has a different atmosphere than most places. The food was all seasonal and of no specific cuisine type. I feel that it's a good option for people who are used to and appreciate organic and local food, but people who feel differently may not like the food. In our party, most of the non-vegetarians ordered the one meat dish on the menu, and found it a bit bland, and the children complained that the food was too spicy. By contrast, one of the vegetarians raved about her dish and wanted to come back every night, and I liked my mangold lasagne, although I found the portion too small.
Note that they do not accept credit cards. As with most German restaurants, expect some smoking.