Article directories are so 2 years ago – most were hit by Panda 1, 2 & 2.1 updates and in my opinion are not worth going after for link equity … seriously, Panda wasn’t simply a move by Google to remove thin content from the SERPs, but another method in combating artificial link acquisition methods.
If you get traffic from this then go for it … but do not continue on with this for link equity … it will eventually all vanish IMO.
If you disagree, then go right ahead and keep going with these antiquated link acquisition methods … it simply makes my job much much easier in the long run