I'm not having any noticeable issues with the plugin, and everything seems to be working great. However, I'm developing my theme at the moment, and because of that have debugging enabled. The plugin is outputting this notice, so I thought I would mention it on here. It looks like something is getting used as a constant by accident on line 62 of the mentioned file.
Notice: Use of undefined constant tab - assumed 'tab' in /home4/mattersm/public_html/the13th/wp-content/plugins/gplus-comments/includes/templates/container.php on line 62