Right, but the original post basically calls for a false comparison (no offense to the pard). Two totally different actors in most ways, both of whom made some really good, really different Western movies.
Apart from many personal differences, they represented different eras and outlooks. I suppose that since they "overlapped", that gives rise to these sorts of comparison questions.
I was born in 1948, but while I grew up watching the great TV Westerns, I never saw a John Wayne Western until I joined SASS in 2004. So I had no sentimentality toward Wayne, and I always have a hard time understanding the Wayne sentimentality that is out there.. But I finally got into Westerns big time back then, and my own personal judgment was that John Wayne was much better, and his movies were much better, than I had expected.
Nobody ultimately had such a great identification with the Western than John Wayne, with the only possible exception in my opinion being Randolph Scott. But while Scott made some of the truly great Westerns, and I have become a big appreciator of his movies, he never came near the larger-than-life quality of John Wayne.
You can't really compare Wayne with Stewart, or Eastwood, or several others. You can compare him in many ways with Scott: he was always the solid, upright, laconic hero. He had a charisma that Scott lacked. But, apart from The Quiet Man, and maybe a couple of other examples, John Wayne was not a great romantic actor. Randolph Scott was pretty good in that department: he always got the girl, and often as not, he stole her from somebody else! Wayne was always kind of being disappointed in love in his movies.....