The Blue Mug Cafe is a really frustrating place. It has the potential to be a great local bar and restaurant, but it's insistence on eschewing waiting staff leads to problems that drive you to look at other local alternatives (such as The Eden Cafe in Magnolia).
Our experience seems similar to others here, long waits in line to order food (especially for Sunday brunch), and long waits for the food to be announced. The food has the potential to be very food but often arrives on the colder side of Luke warm (this could be due to the fact that your food is left on a marble surface apparently underneath an AC vent!).
Another issue is the lack of children, sized portions. My 5 year old is a growing boy but can hardly be expected to tackle an adult sized portion of pancakes!
I truly hope that the Blue Mug Cafe re-assesses its business model and employs some serving staff in the near future so that it can move to become the place that it has the potential to be.