Older V-Ray versions offered a more complicated user interface with too many options.
The Quick Settings offered a particular combination of settings producing the best result for any given scenario. This functionality served to quickly achieve a balance between quality and render time. The Quick Settings also eliminated the need to perform too many render iterations to adjust the proper settings.
V-Ray evolved beyond such overcomplications and now can handle any scenario without the need to select a particular GI engine or image sampler. The settings are now easier to understand and to work with.
Default Settings
The default or universal V-Ray settings currently result in an optimal time-quality ratio with most scenes. They are a good starting point for any scenario. If you want to improve the quality further, please check this article: Render Settings Explained - Quality vs. Render Time