I've tried participating in the RPR beta for Blender on Mac OS, but I keep getting an irritating error message when I try to activate the add-on inside Blender. I've posted the error message at the RPR beta forum and it turns out you need some kind of library which you can install using Homebrew, but I don't want to install and fiddle with another tool just to get the renderer running.

I'm frequently updating Blender with the latest Master builds, and Cycles has an option these days to use both CPU and GPU for rendering. I'm quite pleased with that, and will stick to Cycles, also for compatibility reasons. It's a fine, very potent renderer.