I’m currently in the process of deciding which external renderer to invest in. The 5 main competitors all seems to have their pros and cons. Redshift, Octane, V-Ray, Cycles and Arnold seem to have kicked up a huge war in the Cinema 4D world.
I’ve read multiple articles on the subject and also watched a few youtube videos comparing 4 external renderers. Redshift seems to be the winner in terms of speed but you do lose some of that much sought-after realistic finish. It depends on what each artist is looking for.