"Best of all time" debates are fun, but they are tough because of the different eras involved. Today's game is completely different game than in the 1960's. They are also tough because you can look at stats, or championships, or MVP's, leadership?, comebacks? and you have to consider the team they were on. So to rate QB's is practically impossible and depends on what you personally value more from your QB.
Look at a guy like Aikman who is a HOF QB, with 3 superbowl rings and an MVP but played on a great team, with a HOF RB, HOF WR, behind one of the best lines in history and had some very good defenses to help him out as well. Aikman has great accomplishments, but not great stats. Was Aikman great or was Aikman good but on great teams. On the flip side you look at a guy like Marino who didn't win anything but played on some not so great teams with no RB's and still performed. Marino is definetely in the discussion when talking about all time greats and so is Aikman. Same for a guy like Bradshaw that didn't have good stats at all. He was the leader of the team that won 4 superbowls in six years. He has to be in the discussion. (personally i didn't like Bradshaw, but he would be in the discussion).
Its interesting to see different opinions and especially younger folks that maybe never saw some of the older "greats". I also wonder how an Aaron Rodgers would do passing against the doomsday defense or the steel curtain that would wreck your receivers coming across the middle and there wasn't really a "roughing" the passer penatly . Especially when his skill guys from the 70's would be slower.