I have not been to the Concourse Steakhouse, so I can't help you out with that. However, I will say that the absolute, hands-down, best burgers at WDW are at Pecos Bill Cafe at the Magic Kingdom. I think it might be my favorite WDW restaurant!!!
When we are home (Michigan), that is the number one place we think about eating at when we go back to WDW. Now, I am a big burger fan, and I don't really like food with fancy or unique sauces, so maybe I am biased.
Pecos Bill's has a huge topping bar with not only the usual lettuce, tomato, onions, etc. but also sauerkraut, melted cheese, sauteed onions and mushrooms, etc. so you can really customize it the way that you want.
For what's it worth - it gets my vote for best burgers in the World!
