Hi John,
If you go to Performance >Overview>Agent you can select an agent and see their list of evaluations and a column that indicates a check mark if they have reviewed it.
Additionally - when you open any completed evaluation there is an indication in the lower left corner that indicates if they have reviewed it or not.
In future enhancements we will add more visibility to this, as well as for when agents have left comments on their evaluation.
Hope that helps.
Lesley Veren