what exactly is confusing you ? i take it you are talking about Mental ray since the software render settings havent changed that much.
From Maya 2009 onward the Mental Ray render settings added the passes tab which should not be confused with the old render layers in Maya and is a new feature to be able to render out many different types of passes at the same time in a single render using specific Mental ray shaders , all the other tabs include features that where in Maya 2008 but they grouped simular features under new tabs ...ie indirect lighting tab has the Final Gather and Global Ilumination and caustics and also IBL.
the Quality tab speaks for itself and features anti alias settings for image quality and ray trace settings for shadows ect.