I though I would dig up GW old shader ball scene and give it a go in RT GPU VS Vray Progressive render as RT support way more features that when he started the course.
It turn out that RT GPU wins hand down.
I though it might interest anyone who wondered.
I rendered out a quick turn-table of the shader ball.
Render-time was a average of 2.5 min per frame.
Unfortunately, youtube quality is really bad compared to the raw render.