I went to Dotty Dumpling's Dowry as part of my research into burgers in Madison on a recent trip. I'd have to say that the burger here was perfectly cooked, well-seasoned and constructed of high quality meat.
I got the Rolls Royce burger which is basically a fancy bacon cheeseburger. I thought the Belgian ale cream sauce might have been a kind of gimmick, but it really assisted the burger in a good way. Also, as previously mentioned, the burger was cooked to a perfect medium.
The atmosphere of Dotty Dumpling's is also really quite pleasant and good for groups of four or five to sit at a booth.