1. Component Library vs. Dev Tool: Rebass is a component library for building responsive and styled React UI components quickly and easily, while Storybook is a development tool for designing, documenting, and testing UI components in isolation.
2. Visual Development Environment: In Rebass, components are pre-designed with styling options, making it easy to quickly implement them in a project. Storybook, on the other hand, provides a visual development environment where you can interact with components and see changes in real-time, aiding in the design and testing process.
3. Code Reusability: Rebass promotes code reusability by offering a set of ready-made components that can be easily customized and reused across different projects. Storybook focuses on showcasing and testing individual components, ensuring they are functional and visually consistent.
4. Integration with Existing Projects: Rebass can be seamlessly integrated into existing React projects, allowing developers to enhance their UI with pre-built components. Storybook, however, is typically used as a standalone tool in the development process for creating and testing components.
5. Documentation and Collaboration: Storybook provides features for documenting components, enabling collaboration between designers and developers to maintain a consistent design system. Rebass focuses on providing a set of well-documented components with clear usage guidelines to streamline development.
6. Focused on UI Design vs. Testing: Rebass is primarily focused on providing a set of UI components for design implementation, while Storybook is geared towards testing and refining individual components for optimal functionality and appearance.

In Summary, Rebass is a component library focused on providing pre-designed UI components for easy implementation, while Storybook is a development tool designed for designing, testing, and documenting UI components in isolation.