I’ve ordered the Photography & Rendering book so I’ll report back once it arrives. Fingers crossed it’s worth the not inconsiderable outlay.
Some of the tutorials on Chaos Group are pretty good but as mentioned above, many of them are for older versions of VfR. Personally, I learn better from a structured course that builds in complexity. Adobe do a good jobs of supporting their products, Chaos Group could learn a thing or two from them. Failing that, just a proper manual would be nice. In fact its the basic minimum a new user should expect.