While the sandwich was very tasty, I hesitate to call it America's best Grilled Cheese. I am quite the grilled cheese connoisseur and I'd say the best I've tasted is from my little bakery in the city (with three locations), Amy's Bread. Their grilled cheese challenger, Grilled N.Y. State Cheddar, has spicy chipotle pepper puree, thinly sliced red onions, tomatoes & fresh cilantro. I've tried to recreate this perfect creation in my own kitchen, but have never quite succeeded.
I guess I'll let you decide.