The one key difference with leads vs direct ppc is that merchants who apply through a lead generation engine are usually shopping (so they have applied through many) or they are desperate. If they work then great. I've been around web lead generation since 2002. I've been promised endless returns and hot prospects by literally 100 companies. I came from the mortgage biz. Internet lead gen companies were a dime a dozen. So were call center fax leads. I tried a few that seemed totally legit and every single one was an epic fail.

I have yet to see a single lead provider for the MCA space really make a name for themselves. I've been around the MCA forum for a couple years and every single one there that promised good returns was full of it (or had a @yahoo email. LOL).

I'm not saying the OP's leads aren't as good as he says but I've seen enough in the last 10 years to be skeptical. Very skeptical.