skibum - 3:17 pm on Jun 5, 2009 (gmt 0)
The biggest thing is the match types and the interface. Google is easy to use and you can target well. Yahoo! is cumbersome and the match types need to catch up to Google. Yahoo! dumbed down their system with match driver a looooooooong time ago. While Google doesn't seem to encourage the use of match types, they are in there to give the more savvy advertiser control over the campaigns should they choose to use it.