1. Component Libraries: Evergreen is a UI framework designed to create consistent, scalable, and high-quality web applications. It offers a wide range of UI components such as buttons, modals, and tooltips, allowing developers to easily build user interfaces. On the other hand, react-md is a collection of accessible, themable React components that follow the Material Design guidelines. It provides a set of ready-to-use components like cards, dialogs, menus, and more, which can be customized to match the design of your application.

2. Theming and Customization: Evergreen offers a flexible theming system that allows developers to easily customize the appearance of the components to match their brand's design language. It provides a range of predefined themes and utilities for creating custom themes. In contrast, react-md provides a theming solution based on CSS variables, enabling developers to create consistent designs by easily changing the primary and secondary colors, typography, and other design tokens across all components.

3. Accessibility Features: Evergreen focuses on creating accessible interfaces by ensuring that its components are easily navigable with a keyboard, screen reader compatible, and compliant with WCAG 2.0 standards. It puts a strong emphasis on inclusive design to cater to users with disabilities. React-md also prioritizes accessibility by following the accessibility guidelines provided by the Material Design specification, making its components easy to use for all users, including those with disabilities.

4. State Management: Evergreen provides utilities for managing the state of components, such as hooks for handling form data and managing component visibility. These utilities simplify the process of handling state in React applications and ensure a consistent user experience. React-md, on the other hand, focuses on providing layout and presentation components, leaving state management to external libraries like Redux or React's built-in state management capabilities.

5. Community Support and Extensibility: Evergreen has an active community that contributes to its development, offering support through forums, tutorials, and documentation. It has an extensible architecture that allows developers to create custom components and plugins to enhance the functionality of the framework. React-md also benefits from a supportive community that provides feedback, bug fixes, and feature requests to improve the library's overall quality and usability.

6. Performance Optimizations: Evergreen is designed with performance in mind, optimizing the rendering of components to enhance the user experience and ensure smooth interactions. It utilizes virtualization techniques and lazy loading to improve the loading times of large datasets and complex layouts. React-md also focuses on performance by implementing best practices for rendering, minimizing re-renders, and optimizing the component tree for efficient updates.

In Summary, Evergreen and react-md differ in their component libraries, theming and customization options, accessibility features, state management approaches, community support, and performance optimizations.