In lieu of a Quality tab, in RIS mode the Globals/Settings presents a Sampling tab. This give users control over basic quality via Max Samples and Pixel Variance, the choice of Integrator and its relevant settings, Default Ray Depths, Clamping, Russian Roulette (which can be used for reducing path lengths), and Filtering.
The IPR (Interactive Progressive Rendering) tab is new for RfM 19. It takes over control of the quality settings that were accessed via the "Re-render" window in previous versions - now all these types of settings are accessible in a single window. The settings are identical to the Sampling settings (or the Quality settings if you are in RenderMan/REYES mode), but apply only to IPR renders.