Often when I take a high ISO (relative) I find myself also adding an extra layer of edit ("remove noise") which I think just hurts the image. Adjusting exposure alone I feel does less damage.
I really don't find adding exposure on post (when RAW) damages as much as adding ISO and adding noise.
ISO is really just boosting a sensor sensitivity to light which I feel is not optimal and adds it's own set of artifacts. I would always prefer to add more exposure and me being the one adding the artifacts and playing with the edits, rather than the camera.
But then again, I just shoot for hobby and not a PRO! You can check out some of my pics at @franciscojgo