I think of rendering in Luxrender or Octane, etc., much more similar to taking an actual photograph of a scene than anything else.  Especially since you're dealing with render engines that can reproduce light in very realistic ways, using Path Tracing, and real physical material properties.  It's very much like being a photographer now, and setting up lights like you would in a studio, for a render, and getting predictable results, is a reality now (no pun intended).  So just as you would color grade a photo taken with high end cameras, so too would you correct your photo render.

Not so much the same feeling when rendering with Firefly, because FF still uses very unrealistic techniques to achieve realistic results.  There's lots of workarounds, and it's not just a simple matter of staging a good scene with detailed models, adding real light emitters, and pressing render. It's closer to this than it was several versions ago, but FF is not quite there yet, and certainlly a different procedure than preparing a render for Luxrender or Octane.  Luxrender even accounts for light passing through environmental volumes like air. Firefly, and other non-physics based render engines, is more like taking a photo in a vaccume.

---

Tools :  3dsmax 2015, Daz Studio 4.6, PoserPro 2012, Blender v2.74

System: Pentium QuadCore i7, under Win 8, GeForce GTX 780 / 2GB GPU.