I have an interesting perspective on this free vs paid revelation:
I bought my general directory here on v7n from a great guy over in Egypt. He couldn't accept PayPal payments so he continnued to offer free listings even after the directory reached PR5.
When I bought the directory a little over 2 months back I was getting about 200 submissions a day. It didn't take me long to figure out that THAT wasn't sustainable so I through it into paid mode. When the dust settled I had over 12,000 links live in the directory and another 3,000+ pending approval!!!
Although an industry friend with a lot of experience advised me to just remove ALL of the listings and start over I found that I just couldn't do it. So instead I've been going through thousands of links and pruning out the junk listings. I've got it down to fewer than 7,000 and there's a lot more work to be done. After the upcoing PR
update I'm pulling out the chainsaw and only the healthy portion of the tree will remain.
The point I want to drive home here is that I've seen a tremendous number of submissions that were obviously entered in by robots (human and computer) with no concern over the effect the submission will have on the submitted Website. The problem YOU run into when submitting to free directories is that your link is going to have these links as next door neighbors! No matter how much time you invest in writing a unique title and description the neighborhood is going to be on the wrong side of the tracks.
I don't see how any free directory, including DMOZ, can deliver value for the visitor, submitter, dir owner for very long. The volume of crap submissions flowing in is simply too much to be edited properly by a human.