Clint is the better actor, and I never liked Wayne's political view even though I am a staunch Conservative (he always played the big hero, but in fact was a cowardly draft dodger), so Clint it is for me.
Normally when there are more than 2 pages of replies I don't bother to reply but I feel obligated on this one. NO ONE but J.W. "The Duke" Clint can't even hold him a light in the westerns.
CLINT, without a doubt. I know it borders on heresy, but John Wayne was a lousy actor.
But Robert Duvall has 'em all beat, especially as Boss Spearman in Open Range, featuring the greatest western gunfight of them all. And who can forget Lonesome Dove?
Put me down for John Wayne. I must add though, Robert Duval is currently the best there is. His portrayals of the mature cowboy, rancher or ranger are some of the best I've ever seen.