Superb! One of the best hamburgers I've had in a very long time. Service was very fast, very friendly. Everything was clean. Restrooms were clean. Food was hot, and was delivered fast, too.
Burger was HUGE, juicy and cooked just as we asked. Atmosphere is casual, so jeans are okay, but I wouldn't feel out of place more dressed up, say in dressy casual.
One drawback: a lack of vegetarian fare.