First of all this new Shredder Environmental prop is awesome!!!....
I always mess with things, because my computer is a bit slow....

I did three renders to test Filament vs Iray on my computer....

The first image is Filament - Last Draw
The second image is Iray rendered...
The third image is Iray not rendered - Last Draw (wait on screen render)

I see no difference between the second and third Iray images...

Overall for me Filament for me beats Iray because it is so fast and easy to manipulate compared to Iray.
And I do lots of animations that would take forever to render on my computer....