Having used various article directories over quite a long period now, I can see patterns start to emerge with them. For example, I've noticed that when you submit articles to Goarticles, they do get used by other publishers quite quickly.
Of course that's what you want to happen. However that can also be a problem in that they might not faithfully cite you as the writer, with bio-box links intact. Or if they do do that, they might be using nofollow links -- or the site is just not well regarded by the search engines. If Google then indexes your article at this site before it does at Goarticles (which is PR 3, I think now) then you are being penalized, or at least not getting good value from having submitted there. Outcomes such as those described above have resulted when I have submitted articles there in the past.
But one thing that I've noticed with Sooperarticles, which I'm using more and more now, is that very soon after you get the notification that your article has been published it's right there in Google. So, there's virtually no chance of penalization occurring.
The downside with Sooperarticles, though, is that it sometimes take a while before your article is approved by one of the editorial team. Still, I think that's a small price to pay.