Users appreciate the Google Tag Manager (GTM) Kit plugin for its simplicity, fast setup, and clean interface. It's highly valued for its capacity to handle data layers efficiently and integrate seamlessly with both Easy Digital Downloads (EDD) and WooCommerce, addressing specific e-commerce needs. The plugin's lightweight nature, despite its many features, and the reliable, responsive support team are also highlighted as notable benefits. However, some users express concern about maintaining its simplicity as it continues to be developed. Overall, the plugin is praised for its effectiveness, ease of use, and being a robust, free alternative to other paid extensions.