Paul_AMS - 11:31 am on Nov 22, 2011 (gmt 0)
Yes, USP's (Unique Selling Points) make a huge difference, anything you can do to make yourself different can reap massive rewards.
Per lead has always worked best for me as you have much more control and the payouts are much higher. It's all about testing though, you could start with Per Lead and then do a test with directories at a later date.
Mail me if you want some individual help on how to make more money.