spring-data Vs grails-mapping

A few general questions regarding the spring-data and grails-mapping projects.

- Should one expect that the grails implementations of the equivalent spring-data project be at feature parity?
- Should one expect that all spring-data implementations will be implemented in grails-mapping?
-- If so, in a timely manner?

- If any of the above be no, is there a best-practice available that describes how to use spring-data with a grails based project?

Thanks much

(cross posting this to the grails forum as well)