Thanks for this plugin. It works like a charm.
We just had an error though when we upgraded the plugin this morning. I went to the WP admin panel and selected to upgrade the plugin automatically. However, the site did not respond any more after the plugin was re-activated.
I moved away the plugin folder to have WP de-activate it and run the site. Then I went into the code itself.
It seems that the file
mailchimp-widget/lib/ns_widget_mailchimp.class.php has got some lines leftover after a merge on lines 14-18 and 266-270. I kept the lines coming from HEAD, and all went back to normal. This problem seems to be on all downloads for this version since I downloaded it on my machine directly from this site and had the lines.
Hope this helps !