netmeg - 1:54 pm on Jun 5, 2012 (gmt 0)
My criteria for directories is pretty much limited to 1) they have to be relevant, 2) they have to be strictly curated - not just anyone can get in, even with a credit card - and 3) they have to be directories that human beings actually deliberately visit, and not directories that only exist for the purpose of links. Payment doesn't enter into it - if it's a good directory that will provide traffic, I don't mind paying for it, and if it's curated, and relevant, I don't see anything wrong with it being free.
That filters out a lot of the garbage and it has worked out pretty well for me and my clients.
(Of course, there aren't a whole lot of directories like this for every niche)