maybe in 10 years you can look back and compare accomplishments - but even then much of that will have to do with circumstance. I think the flood of analytics based websites has turned everyone into an evaluation 'expert' 'His QBR was this...they're ranked 25th on this metric', blah blah blah.
At the end of the day - did you win more than you lost and did you give your team a chance to compete for a championship or 2.
The rest is just too much data that's difficult to draw meaningful conclusions from.