Google Website Optimizer: Split testing posts, pages and themes, best plugins?

Seems like there’s been a number of plugins on this, anyone using any of these and could suggest which to use? I found these two below as it seems there is not one plugin that can test both themes and posts/pages.

http://wordpress.org/extend/plugins/wordpress-ab-theme-split-tests/
http://wordpress.org/extend/plugins/google-website-optimizer-for-wordpress/