Arnold Render is just so pleasing to work with

As an unbiased renderer it does not have all those annoying mad hat settings that Redshift has. What time you may save on an RS renderer is off set but the fast ease of setup of Arnold. You also have no worries about a GPU running out of memory and it can take as many CPU’s as you throw at it. For the price of a good Niviida card i can buy a dual 10 core Xenon rig with 40 threads.
And joy of joys, shading is a dream because you need not shader. Arnold can tale all TFD shading information directly from TFD’s shading tab.
Yes RS may be the engine of choice for many situations but for TFD I am finding it far more amenable and it just does what it does and your only really concern is manipulating the AA settings which are very well separated for such things as diffuse, GI, reflections etc.
My Tutorials

Redshift is a fast render engine once it loads a TFD file. A 300MV voxel frame takes a minute to load and 5 seconds to render !! Sometimes you can make adjustments and feedback is immediate other times it want to reload the TFD file and then C4D will freeze for a minute while it loads up the file again…VERY frustrating. I also find shading VERY tricky. For a still it is fine, for a cloud not bad at all but for an explosion you are continually having to adjust the shading depending on what stage the explosion is. Of you get the late stages fine the early stages are blown pout and washed out. AR does this well enough with a blackbody emission, you set and forget it and Arnold of course can do the same. The load times and the continual messing around with settings means I can render an animation in full in Arnold by the time I have my 10th frame, at best, rendered out of Redshift