Octane VS Corona

[geo_n]

Biased rendering has its place. Bake the background and render biased mode and render moving elements in bruteforce mode. This is still fastest way.
Redshift has a lot of high quality animstions in its gallery.
There was a corono vs kray scene and kray is superior in speed and quality.

[geo_n]

Here's a benchmark scene
http://corona-renderer.com/stuff/a4-benchmark

Extract and run corona.exe and wait for clean render.