Note that PIC applies to in-camera jpg images only, not RAW
... and rightly so - with an overexposed shot, the vignetted corners will be brightened in jpeg with in-camera correction though they are exposed correctly. And then the exposure of the whole thing is lowered in postprocessing resulting in a loss of dynamic range in the corners.
If shooting jpeg, I'd still turn off in-camera processing unless I want the shots to be used out of the box - postprocessing with dpp, acr and the like won't be worse and adds more flexibility. The only reason to turn on in-camera processing is with small jpeg+raw to quickly see what the camera would have done as a reference for raw conversion.