Andrew,
I have used them for a few months now. So far I have gotten on average at least a few jobs per month. My ROI has been around 4:1 so far.
FYI – you can negotiate a lower rate than what they initially give you. Also, they want you to sign up for 12 months, but that can be negotiated as well. Just need to speak to a person above the sales rep level. I got my monthly territories increased and fees reduced while only signing up for a 6-month contract.
Dan