There's a few things to note:
• 'post effects' like bloom and glare are actually pretty useful.
• Panoramic is worth looking at.
• Camera distortion is controlled via a slider. I'm not sure if this is influenced by the focal length at all or if it's an arbitrary effect, it seems to be able to push to extremes in terms of pinch and bloat.
• 'Colour Mapping' (as it is in Vray) doesn't seem to exist. You have the option of using Linear colour space or there's a long list of film types to choose from. These have a massive impact on the colour and contrast sensitivity. Neither image had any 'post processing' outside of Octane. Both had their film type changed on the fly while rendering - the high contrast image will actually be slightly higher quality in terms of samples because it rendered slightly longer - despite the noise being emphasised.
What all of these things mean for me initially is that I'm not sure how simple it would be to bring in real world values from a shoot and match to a plate mathematically (I'm sure it is possible) . But it does offer a huge amount of artistic control to really play around with how you want an image to look.