How can Yahoo Search Marketing compete with Google Adwords in PPC Advertising, effect

What are the reasons why Yahoo, despite its initial headstart (Go2.com, Overture, etc.) over Google in PPC advertising, is not anywhere close to Google Adwords in either market share for itself, or gain ‘win-win relationship image’ in terms of customer perception?
Can Yahoo do anything to bridge the gap, and even overtake Google in PPC advertising? How?
This is just to clarify based on the first response below. I’m not sure if it is purely a matter of personal preference.
Advertising is a business market, where only results would count, unlike consumer markets. When it comes to money making, the market is very efficient and ruthless.
Besides, advertisers don’t have to choose one of them over the other, as they could use both, if both would produce results for them.
Are there specific features and benefits of Google’s over Yahoo’s that advertisers prefer? For example, Bid policies, minimum bid rates, conversions to sales, […]

Original post by MrPJH