Absolutely a fantastic idea to pair hamburgers and frozen yogurt!!
We came here on the 4th of July weekend to fill our hamburger cravings. I like the fact you can create (as the name implies) your own hamburgers, more so the fixings than the patty itself. It's great how they have a variety of buns, toppings and endless sauces to go on the side. The fries also come in regular or sweet potato versions. I always go with the latter.
No complaints here just good food. After eating my entire hamburger and fries, I ordered the Smithsonian Masterpiece: 4 scoops of vanilla frozen custard, chocolate syrup, caramel, nuts and whip cream. It was overkill. I could not control my need to super size everything and fat out.
My only suggestion is to limit the desert or you may be lethargic for the rest of the day!
By the way the staff is so friendly and attentive. A + for that.