When you work with real DOF or Motion Blur the Vray cam is the best option, because its value is very seems to real world camera like shutter speed, ISO and aperture and is more easy to reach the desired result. I’m not agree that you need a Vray cam to get a real render but if you need some aspects in your render a vray cam is a easy way.
About lights I’m used to use booth options, vray and standard light. Vray light provides a specific result, in this case the important is the nature of the light font. With vray light you can easy simulate a illumination provide by a window or a chimera light (http://www.izzyvideo.com/images/izzyvideo85.jpg). It’s hard to obtain the same result with a Spot light and VRayShadow with Area shadow and demands more time to render. In Vray Light you can simply turn on the option to Store with Irradiance Map and therefore get a fast render with a beautifull light.
VRayIES and VRaySun works fine and fast with Vray than the max option.
To put it shortly: many situations demand specific light and camera and you’ll learn how to manage this in your workflow.