Users appreciate this WordPress plugin for its reliability over the years, easy configuration, and useful features like displaying a list of email campaigns and latest newsletters to entice sign-ups. They value the precise and simple shortcode options that make creating an attractive and functional newsletter archive effortless. Additionally, users like that the plugin allows control over the displayed newsletter size and provides links that open in a new window. However, significant drawbacks include its reliance on the outdated MailChimp 1.3 API, lack of updates for four years, height constraints on newsletters, and occasional issues with the "Show More" feature, requiring users to modify the code themselves.