Users appreciate the Sumo plugin for its effective email list building, heatmap, and A/B testing features. The drag-and-drop editor and clean UI are highly valued, along with the relative ease of installation and configuration. Some users receive outstanding customer support, often highlighting specific representatives for their helpfulness. However, many users criticize the plugin for being overpriced, with limited useful features in the free version. The plugin significantly slows down website speeds and often disconnects randomly, causing frustration and hindering site performance. Customer service is another major drawback, frequently cited as unresponsive or unhelpful. Some users also face difficulties with browser compatibility and persistent advertising even after uninstallation.