My opinion is ' no backlinks' is better than duplicate content. Quaility and unique articles submitted in High Pr article submission sites do really work. At least worked for me. My accepted articles in ezine articles helped my rankings. They were not written perfectly as I am not a native English speaker but the content was good enough to be accepted. I have only 3-4 articles submitted and already ranking good.
But I do not have any answer to your second question and would love to hear what others will say about it but I can say that I bookmark the articles in my website instead of submitting them to article directories. I also bookmark my accepted articles to drive indirect traffic to my website.