Hatchet, I pay service magic per lead. I can review it and choose to accept or decline it. This is my preferred method of lead generation. It allows me to weed out the crap. They always try to get me to switch to the method you spoke of however I refuse. There are ALOT of crap leads coming through service magic and the other services, but there are alot of leads!
Another thing you MUST remember is these leads are HIGHLY competitive. If you don't accept the lead within 6 hours, don't waste your time. If you don't call them immediately after accepting the lead, don't waste your money accepting.