Since YUI3 has no recommendad usage scenario, I would submit for consideration: Use YUI3 if you want a comprehensive framework that includes DOM manipulation a

Since YUI3 has no recommendad usage scenario, I would submit for consideration: Use YUI3 if you want a comprehensive framework that includes DOM manipulation and event handling along with a highly consistent set of widgets, layouts and utility components all in one package. At least, this is when I choose YUI over arguably lighter / smaller / simpler solutions (like jQuery).