Are there any useful Silverlight Frameworks?

Are you using any framework (like Prism or Unity)? What are your experiences with them and are they mature enough to use in production apps?

I would like to create a complete list of all frameworks:

• Prism (Guidance, MVVM)
• Unity (DI/IoC)
• Enterprise Library 5.0 Silverlight Integration Pack (Validation, Logging, Exception Handling, Caching, Interception, flexible config)
• Ninject (DI/IoC)
• .NET RIA Services (Data)
• MEF (Extensibility)
• MVVM Light Toolkit (UI Patterns)
• Caliburn (UI Patterns)
• Silverlight Extensions (Controls/UI Patterns)
• Silverlight Toolkit (Controls)
• Silverlight Contrib (Controls)
• Silverlight Unit Test Framework (Unit Test)