Both quite complex men, it's difficult to say who is more interesting, but with the insights to Boromir's mind and his turmoil that Tolkien gives us, he wins it by a whisker I'd say. I love his chunnerings all the way down the Anduin as he fights to allow himself to be led by Aragorn. His death scene is ace (and who hasn't tried to draw a picture of it, eh?
). And he wasn't led astray by some strumpet in the woods, either....just by an um...magic ring.....
++Boromir