@mrittman The reflectance channel works with Standard and Physical Renderers. It replaced the standard reflection channel. But my point is, that interface you're showing in C4D, only shows up like that when you create a Corona-specific material. It has it's own tabs and options. C4D's isn't less confusing, but I didn't want people to get the wrong idea.
So in that reflectance tab, you can add many layers of materials, textures and effects. Topcoat just adds a nice GUI to the process and adds a bunch of easy-to-use features such as bumps, dents, lots of bumps, blurs, metallic presets and so on. I can make a complex material quickly without know how the deep controls of the reflectance channel works.
Anyway, they're working on a nodal system anyway so this is a moot point, right?