Do you recommend the integration with other frameworks? The two that I would like to know are: Struts and Spring
Or no, the integration doesn't worth all the problems that might result, and the developer should choose one of them?
From my experience I'd say Struts + JSF isn't worth it, pick one. The Spring + JSF should work just fine and have decent integration (though with CDI, what would you need Spring for, beside using it simply as a library?)
Weld provides an uberjar (single JAR) that provides everything you need to use CDI in a servlet container (such as Tomcat or Jetty). The best way to get started with CDI (whether in a servlet container or Java EE application server) is to start with the Maven 2 archetypes provided as part of the Weld project: http://seamframework.org/Documentation/WeldQuickstartForMavenUsers