Well, I think you know that my answer is going to look a lot like yours. I don't really like GOAT, because it is impossible to cross huge generational gaps. Is Tom Brady really better than Johnny Unitas? Or is it just a different time?
I don't think Elway or Payton get into the conversation, great though they were. Marino had some seasons, but I don't think so.
I think truly we are talking Starr, Unitas, Montana (sorry Steve Young :)) and Brady. Namath and Brees have had some years (on both sides of greatness). Len Dawson? Fouts? Not so much.
Brady it is, Brady it will be for me. If only he wore high topped shoes he'd be damn near perfect.