Ask YC: Google Vs. Yahoo for traffic

I've got about 3 web sites going which I actively advertise for and am noticing a consistent trend.

1. For organic traffic - while most of the raw traffic of my site comes from Google, Yahoo has a noticeably lower bounce rate and higher daily conversion rate.

2. For advertising traffic, Yahoo's advertising engine delivers noticeably higher quality leads then Ad words (although, again, less of them).

So I'm extending the question out to the community - who treats you better in terms of both organic and advertising ROI? Yahoo or Google? In terms of both quality and volume?