I get around 40-50 visitors / day from Directory Critic. As someone stated above, it depends a lot of the position of your directory on the list. If it's free, well that's much better.
I would agree with this - it seems to me the traffic that visits DC is looking for free directories. If you have a free one you may get some traffic from them. If your offering a paid directory you may want to look elsewhere.
Good post. Too the point and shows the place is used by no-one other than fellow directory owners looking for a free link.