Adsense Alternatives- Yahoo Publisher vs Google

I found an interesting link on a German Blog to a comparison chart showing the differences between Google Adsense and Yahoo Publisher Network (YPN). At present YPN is only available in the US, and by invitation only. Publishers have reported much higher per-click payments but they say the clickthrough rate can be lower with YPN due to poor ad targetting. I am looking out for developments with Yahoo's Publisher Network.