Many times, people confuse the actor with the man...by that I mean, an actor can convincingly play a character, or the same character many times, so that people think that it represents the man...when in reality, the man may be nothing like the character.
In John Wayne's case, though, I believe he was not so much an actor as he was a man playing himself. Perhaps it was only his own opinion of himself, but even so, he generally remained true to what he thought of himself in his characters. Even when he played somewhat less admirable characters in movies like The Searchers, wherein he was flawed, tormented, and almost an anti-hero, he still had the courage of his convictions and stayed true to his own moral code.
John Wayne was human...we tend to elevate our stars and professional athletes to god-like status, and forget that they too can make mistakes, have faults, and be less than perfect. I think his reasons for not serving in the military were complicated; the studio pursued several exemptions on his behalf, without his request, after he failed to contest his classification as 1A. He didn't protest their actions, though, motivated in part perhaps by their threats to sue him if he tried to serve, because of his contracts. Would they have really done so with the patriotic mood of the country at the time is questionable...but still, the threat was there. I think he regretted it for the rest of his life, and was embarrassed that he did not serve, especially since he loved America and wanted to be an advocate for her. How many of us have done something in life that we later regret? I know I have.
I like many movies, and I like many actors...so it is hard to say that I like one single actor better than all the others, for they all offer a different entertainment factor. As for the human beings themselves, in many cases I don't think I would like them in person. In the case of John Wayne, though, I think he would be a man that would be good to know as a human being.
My all time favorite John Wayne movie is not a western...it is "The Quiet Man."