Article syndication is essentially a barter relationship - one in which the content creator usually loses in my opinion.
Article directories work hard to accrue trust and authority. They do so by building backlinks to their directory. The aggregation of all that content is valuable (to some) and so they work hard at acquiring backlinks.
Content (and site) owners seek to get a link from domains with a high degree of trust and authority. The barter arrangement is content in exchange for a link (or two).
It's that content which allows the directory to continue to operate. Without that content, they wouldn't provide value, nor would a link from that directory mean much.
Here's the rub - search algorithms are looking for domain diversity - getting quality links from a variety of different domains. So, in this situation, you're allowing the directory to build that domain diversity. They use your content to build many backlinks from various domains. All you get is one solid link from the directory.
If you have the time and ability, use your content (your intellection capital!) and build those backlinks yourself. Why let someone else use your content to build a business and then lease back a portion of the value back to you?