1. Ease of Use: Expo Sketch is a platform specifically designed for creating mobile apps using React and React Native, providing a straightforward interface for beginners to quickly develop and test their ideas. On the other hand, repl.it is a versatile online coding platform where users can write, compile, and run code in various languages, making it ideal for a wide range of programming tasks beyond mobile app development.

2. Deployment Options: Expo Sketch simplifies the deployment process by allowing developers to preview their apps directly on mobile devices through the Expo Go app or by generating standalone iOS or Android builds. In contrast, repl.it focuses on providing an integrated development environment (IDE) for coding without built-in specialized deployment features like Expo Sketch, requiring additional steps for deploying mobile apps.

3. Community Support: Expo Sketch benefits from a dedicated community of developers focused on mobile app development with React Native, providing a wealth of resources, tutorials, and forums for assistance and collaboration. repl.it, while offering a supportive community for general coding projects, may not have the same level of specialized support and resources for mobile app development specifically.

4. Collaboration Tools: Expo Sketch offers features like sharing projects via QR codes or links, allowing for easy collaboration among team members or sharing with stakeholders for feedback. In contrast, while repl.it supports collaborative coding with features like shared coding spaces, the platform may not have the same user-friendly collaboration tools tailored for mobile app development projects as Expo Sketch.

5. Extensibility: Expo Sketch provides a curated set of components, libraries, and APIs to streamline mobile app development, offering a more structured development environment with pre-configured tools. repl.it, as a more general coding platform, may require users to configure and integrate external libraries and tools themselves, offering greater flexibility but potentially requiring more setup time for mobile app projects.

6. Learning Curve: Expo Sketch, with its focused approach on mobile app development using React Native, may have a more gradual learning curve for beginners compared to repl.it, which caters to a wider range of programming tasks and languages, potentially making it more challenging for newcomers to navigate initially.

In Summary, Expo Sketch is tailored for rapid mobile app prototyping with specialized deployment options and community support, while repl.it offers a versatile coding environment with collaborative features and extensibility but may require more configuration for mobile app projects.