Auto Credit Express sent me a ton of leads in the past. They have a decent scrub policy. However, a number of the people we spoke with about vehicles were under the impression they could get a car for no money down. ACE insisted they never had any of that messaging on their sites.
Otherwise, it was a decent volume of leads, the hiccup of our banks wanting 30% down, and the buyer wanting 0% was a sizable hurdle to overcome. So, we did not stay with them for long, other stores in my group did continue using them though.