Diagnostic Clinical Genome and Exome Sequencing

In “Diagnostic Clinical Genome and Exome Sequencing”, Biesecker et al. are critical of the way doctors have been ordering CGES tests in the past and offer new factors for a doctor to consider before ordering the CGES test. They define the basics of CGES testing and suggest various measures that should be taken prior to placing an order for CGES.
How effective is the comparison between exon and genome sequencing? Can an argument be made to support one over the other using the information provided? What can you do with the given information to make a case for one over the other?