The main advantage of using the Spring DSL

The main advantage of using the Spring DSL is that you can now mix logic in within your bean definitions, for example based on the environment :

import grails.util.*

beans {
	switch(GrailsUtil.environment) {
		case "production":
			myBean(my.company.MyBeanImpl) {
				bookService = ref("bookService")
			}
                break 
                case "development": 
                        myBean(my.company.mock.MockImpl) { 
                               bookService = ref("bookService") 
                        }
                break 
        } 
}