YPN on a per click basis paid more during my trial for the niche of my site...however the ads werent targeted and releated, so I went back to adsense full time.
I had YPN on the same pages as Adsense (I removed Adsense temporarily). I found that YPN revenue was about 15% of the total adsense revenue for the same pages. Also, YPN ads were not relevant to my site. It seems the YPN inventory is not as good as Adsense. I tried YPN out for 1 week and I was not satisfied so I removed them. Then I got a phone call from a YPN rep asking why I removed their ads. I told him YPN SUCKED!