I love Manning and argued him as the best for years. I hate when people say Brady is the best because of the superbowls. Brady played under the greatest coach, and for a much more well run organization.
It’s eye test for me. Regular season, Manning was a comeback machine, and very clutch. While I don’t think he was a “choker” postseason, he definitely wasn’t as good, and there were a few big moments where he seemed to shrink - almost like he didn’t want to be there.
By contrast, Brady seems to live for those moments in the biggest stage. Ice water in the veins. It’s a pretty rare quality in athletes, and the only guy I’d put on that level is Jordan.
Manning is more like Lebron. Amazing and both more clutch than they are given credit for, but they also have disappeared at key times.