I started using relative paths, but later changed to root relative instead. My experience is that it doesn't make any difference.

Absolute and Root Relative Paths are however better when using mod_rewrite, as your links to CSS files and such otherwhise simply break.

Hi
Absolute URl is much better as comparison to relative URL on the SEO point of view.

Thanks
SEO Tools

relative path is better than absolute path because absolute path increase your page weight