1. Architecture: React Redux follows a unidirectional data flow pattern, where data flows in one direction, making it easier to trace the changes and manage the application's state efficiently. On the other hand, Sugar is a simple and lightweight library that deals with local state management and UI components without following a strict architecture like Redux.

2. Global State Management: React Redux enables centralizing the application's state in a global store, making it accessible across multiple components. This allows for better data sharing and consistency throughout the application. In contrast, Sugar focuses on local state management within individual components, which can lead to a more granular approach to handling state but might result in duplicative data across components.

3. Middleware: In React Redux, middleware can be added to intercept and process actions before they reach the reducers, allowing for advanced functionalities like asynchronous data fetching and logging. Sugar, being a simple library, does not offer middleware support, making it less suitable for complex data flow requirements that need middleware functionalities.

4. Community and Ecosystem: React Redux has a large and active community, with extensive documentation, tutorials, and third-party libraries available for additional functionalities. On the other hand, Sugar, while being a lightweight option, may have a smaller community and fewer resources for support and expansion.

5. Performance Optimization: React Redux provides performance optimizations such as memoization and selectors to prevent unnecessary re-renders and improve the application's responsiveness. In comparison, Sugar focuses more on simplicity and ease of use, potentially sacrificing some of the performance optimizations offered by React Redux.

6. Learning Curve: React Redux has a steeper learning curve compared to Sugar, especially for beginners or developers new to state management libraries. The concepts of actions, reducers, and store can take time to grasp fully, whereas Sugar offers a more straightforward approach to managing state within components.

In Summary, React Redux offers a robust global state management solution with a structured architecture, middleware support, and performance optimizations, while Sugar provides a simpler, lightweight option focused on local state management within components, with a lower learning curve and potentially less community support.