Surface model - Glisur or Unified

Dear experts,
I’m dealing with Optical photon simulations. There are two surface models - glisur and unified model. I am wondering which model is more accurate? Are there any references studying this question?

As I understand it the Unified model is meant to replace the Glisur model. Both models require the user to define various parameters. The accuracy of the model will depend on the accuracy of these parameters.

Thank you for your answer!