Revel vs. Atmosphere vs. Yii

Revel makes it easy to build web applications using the Model-View-Controller (MVC) pattern by relying on conventions that require a certain structure in your application. In return, it is very light on configuration and enables an extremely fast development cycle.

The Atmosphere Framework contains client and server side components for building Asynchronous Web Applications. The majority of popular frameworks are either supporting Atmosphere or supported natively by the framework. The Atmosphere Framework supports all major Browsers and Servers.

Yii comes with: MVC, DAO/ActiveRecord, I18N/L10N, caching, authentication and role-based access control, scaffolding, testing, etc. It can reduce your development time significantly.