The true value for an IMO is if they can get the troubled cases placed as well as the good cases. I would ask for their record on placing rated cases and the ability to get the better classes for reps. My IMO helps with the tough cases and has obtained offers where others have not been able to get it past the initial questionnaire.
In addition to this, I would ask what their process is for case development. If they simply run illustrations, then maximizing the client need will not be met. A good IMO will offer help to make sure all the options on case design are covered as well. I would take an actual case to a few of the organizations to test their capabilities.
Last, I would ask for references from other agents. This is probably the most effect way to evaluate IMO’s.
These services, in my opinion, are the most valuable part of the relationship. Once you are happy with their answers, then check into compensation questions.