Users appreciate the Slim SEO plugin for its lightweight design, ease of use, and absence of unnecessary bloat. It simplifies SEO tasks with features like automated meta titles, descriptions, and XML sitemaps. Users also commend its integration with Meta Box and minimalist codebase that doesn't slow down websites. However, drawbacks include problems with multilingual support, some plugin conflicts, and occasional bugs in features like redirection and link updates. Some reviewers also noted a learning curve for advanced customizations due to limited visual settings, relying instead on hooks and filters. Overall, it's praised for making SEO accessible without overwhelming features, perfect for both beginners and experts.