I was thinking about trying them out but wanted a little feedback. Also, I'm referring to their sponsored placements.
I don't know about their sponsored placements, but I submitted my site to them and they added it to their list. Now I get a regular stream of traffic from them. Nothing monumental, but it's consistent. I have submitted to a variety of blog directories and blogcatalog is the only one I've received any traffic from. If their free basic listing works that well, I would think that their sponsored placement would at least be worth a try to see how it performs.