This is a test I rendered in 3DS Max using FinalRender (I also did a test with Mental Ray) with no lights in the scene, using an Ambient Occlusion Map as a mix map for the textures of this race car from Daz3d. I also applied the Occlusion map to the ground plane. Average render times were about 10 to 15 seconds. This is a life saver when rendering preview animations and architectural simulations. The advantage is that you get renders that look like they are ray traced and with details that pop.

Rendering the same scene using lights and final gather, and then applying an occlusion map as an override, and then heading to your compositing program to put everything together, can result  in multiple steps and relatively long renders. But with this approach, I have been able to create nice demos that look nice without sacrificing on the lighting quality.

Here are some more renders.