allot of it has to do with the topic and of course the interest it creates in other people just keep trying new stuff!!
Im fairly new to article marketing, however after submitting a few of my articles to the popular article sites they do seem to help my search engines rankings. The articles dont rank to badly either if you stick to less competitive keywords.
I too am using articles mainly for a long term gain in SEO. I normally don't see gain right away.. it takes time.