WebMotion is a Web application development framework based on a REST architecture and the Java EE 6 standard. It features a presentation layer management using pages (JSP, HTML, etc.) and REST service exposition (e.g. XHR calls). It enables you to serialize service results into JSON or XML. The framework has deliberately limited capabilities, but it focuses on the ease of use. It leaves open the choice of persistence framework, dependency injection, and validation.
VRaptor3 is a fully-fledged Java Web framework focused on fast development and maintainable code. It intends to make RESTful application development easy. A resource corresponds to a business logic annotated with its path and HTTP method. It runs inside DI Containers (Spring or Pico out of the box) and, therefore, enables full integration with them. Also, using Hibernate is easier: its session is automatically injected by VRaptor, so you just have to use it. VRaptor3 is refactor-friendly, especially in its redirecting configuration. It is also nicely extensible.