I do not agree that Yahoo is easier. From my experience I can say that Google is a lot more predictible (I don't say easy) - you build a site, update content regularly (don't forget about wisely balanced onpage SEO), get as many backlinks from authority pages as possible - and you are up.
With Yahoo it seems they are from another planet. Sometimes it's just enough to have a simple article directory with content around your niche. And sometimes you even this with nice amount of backlinks (even for quite simple keywords) is not enough.
Paradox!