1. MVC Architecture: Django follows the MTV (Model-Template-View) architecture, Laravel follows the MVC (Model-View-Controller) architecture, and Rails also follows the MVC architecture. The key difference lies in how each framework handles the separation of concerns within the application.
2. Language: Django is predominantly written in Python, Laravel is based on PHP, and Rails is built on Ruby. This impacts the syntax, performance, and community support for each framework, depending on the language used.
3. Development Speed: Laravel is known for its speed in development with its intuitive syntax and robust set of tools, followed by Rails, while Django is considered to have a steeper learning curve, especially for beginners, which can impact development speed.
4. Security Features: Django provides built-in security features like protection against CSRF attacks and SQL injection, making it highly secure by default. Laravel also offers security features but may require additional packages for certain functionalities, whereas Rails is known for its focus on convention over configuration that enhances security.
5. Community Support: Laravel has a large and active community that provides extensive documentation, tutorials, and plugins to facilitate development. Rails also has a strong community backing, while Django has a supportive community but is relatively smaller compared to Laravel and Rails.
6. Flexibility and Scalability: Laravel offers flexibility with its modular architecture, making it suitable for small to medium-sized projects, and can be scaled with additional components. Rails, on the other hand, is known for its scalability and is preferred for large, complex applications. Django falls in between with decent scalability options and flexibility for various project sizes.

In Summary, the key differences between Django, Laravel, and Rails lie in their architectures, programming languages, development speed, security features, community support, flexibility, and scalability.