The plugin's core functionality seems good, but there are tons of warnings coming up everywhere when PHP is set up to show errors and WP_DEBUG activated.
This may not be a seem as a huge deal on a production site when errors are hidden and WP_DEBUG is not in use, but it's a pain when using this plugin in a dev environment.
Please turn on WP_DEBUG, show errors in PHP, and clean things up. The issues are pretty trivial - mainly lack of checking if variables are set before using them (especially before options have been saved).
http://codex.wordpress.org/WP_DEBUG
http://php.net/manual/en/errorfunc.configuration.php
http://wordpress.org/extend/plugins/debug-bar/