One of the issues we face in responsive theming is on-browser performance across multiple devices. Responsive themes are inherently more taxing on rendering engines, but once we add to the page all the interactive bells and whistles (ex: sliding banners, videos, flying objects) we might be setting the browser up for a serious impact on rendering.

John Hannah at Friendly Machine wrote an in-depth look at this issue, and offers some solid advice in the field of responsive performance: