Here is a possible start for this comparison:
BETWIXT http://jakarta.apache.org/commons/betwixt/
XML Beans http://xml.apache.org/xmlbeans/ http://dev2dev.bea.com/technologies/xmlbeans/index.jsp
Schema2Beans http://schema2beans.netbeans.org/
JAXB http://java.sun.com/xml/jaxb/index.html
JSX http://JSX.org/
Koala http://koala.ilog.fr/koml/
JBind http://jbind.sourceforge.net/
Castor http://castor.exolab.org/
Kawa (Does this belong here?) http://www.gnu.org/software/kawa/
Breeze XML Binder http://www.breezefactor.com/
XGen http://www.commerceone.com/developers/docsoapxdk/xgen.html
xstream http://xstream.codehaus.org/
Here is a link that compares Breeze XML Binder, Castor, JAXB, and XGen http://www.xml.com/pub/a/2003/09/03/binding.html