I would be hesitant to rank them against each other as they all have their outstanding qualities. Rather, I would say that they are all in the same class, offering excellent quality and great flavor.
I would also include in that class, burgers from Tessaro's in Pittsburgh, and Lion's Tap, The Nook, and 5-8 Club in Minneapolis. Other excellent choices, though not quite
as good as those just mentioned, are Sobelman's and Kopp's in Milwaukee.
I've probably forgotten one or two, and for that I apologize. Should something occur to me, I will add them to the list. I know there are plenty others out there that I haven't yet tried. I look forward to the opportunity.
nocarolina, I know that Hackney's is another of your favorites, but it's been so long since I've had one of their burgers, I will decline to comment one way or the other. As I recall from my youth though, they were pretty darned good also.