Hi Brian.
My experience with Dealix was always superb during my career with 3 different franchises (prior being w/ Cobalt) as well as after, now with my current employer. The leads had a cost between $20,50 to $19,00 depending on the Group negotiation. Crediting was never an issue especially with their 100% quality pledge. Closing ratios were on the 3rd party front lower than the website generated leads but with +8% in my favor.
I cancelled several times AutoUSA leads. Once vecause of the arrogance of the local rep, and twice the lead quality was definetively not there wher it should be, meaning the duplicate leads most of the times was already in my CRM, delivered minutes and sometimes even hours prior by Dealix.
When you were waiting too long to send these duplicates back, AutoUSA tried to "escape" and not to refund (2009) these leeds becasue of the 30 day turn-in limit time. Pricing was attractive ($13,50) but really what helps a small fee, when the lead was "too old". Time is the essence on 3rd party leads as everybody knows. The closing ratio was < 2% and therefore not worthwhile to consider any longer.
So my choice will be always Dealix first, and when necessary Autobytel second before considering AutoUSA.