Looks like someone had to spent a lot of time modeling all these details
Where did you find these pics?
I use Vray to make archviz because its ideal for many light bounces (interiors) and animations. Lightcache is something special indeed.
Productviz is a different story. Less GI bounces, faster renders. I switched to Fry a year ago because I believe that a true future lies in this technology.
It's physically based all the way, not like Vray which lacks a physical material model. Besides this Fry is unbiased. Imagine rendering same scene using Vray PPT or QMC+QMC it would take days, and would be still biased... Fry, Maxwell, Indigo etc. are simply faster when you need highest quality.
15 hours was long but it was on my old system. Now it would be ready after 6 hours.