Is there any difference how the css3 effects (for example animation) are rendered if the doctype is defined as
(html5)
or
Yes it does, and I can tell you that from personal experience.
HTML pages which consist of sliced tables that have no cellpadding and cellspacing, fail to work with a HTML5 doctype. I had to use HTML4 transitional.
HTML pages that use grid layout systems can sometimes work better with a HTML5 doctype. I find that the Tiny Fluid Grid does not work with a HTML4 transitional doctype.