I am a big fan of Yahoo! Sponsored Search over Google’s AdWords for the following reasons:
Yahoo!’s user interface is deeper and more dynamic than Google’s.
You can get extremely precise tracking in a really easy manner that doesn’t take much clicking or site digging.
Yahoo!’s budget management is more flexible.
Yahoo!’s keyword setup is faster and clearer for first-time setup.
Yahoo!’s click-through rate is higher per impression.
Yahoo!’s bid position process is more transparent.
Yahoo!’s entire setup feels more established, cleaner and solid.
Give Yahoo! Sponsored Search a try if you want to get the word out about one of your websites. If you currently pay to play with Google AdWords, you definitely need to move up to Yahoo! Sponsored Search instead.
I believe Google is trying to demonstrate higher accountabilty for users by setting Bid position not only based on bid amount.