This is a tough question. How do you rate them?
-By railfan fantasy of running the biggest network on the map with the nicest services, IE dining, sleeper, baggage...
-By revenue, profit, other financial measure
-By political success in increasing funding, capex, etc...
-By social good, IE moving the most passenger miles per dollar of subsidy or total budget
Because there is a different answer to all of those measures.
Claytor might be the best all-around president. The early (pre-reistrup) guy who turned down massive funding might be the worst. I'd also suggest the guy who decided to get creative with rolling stock instead of sticking to best practice might be on the awful list, because he hobbled the railroad forever with bad ideas, bad culture, and bad image with passengers and host roads that have to put up with the BS of failed equipment.
The new Acela: It's not Aveliable.