In perusing a couple of popular CG images, most of the gushing but non-substantiative comments came from non-CG people, and that about half of the CG people's comments were substantiative. Furthermore, most of the CG people who gave non-substantiative comments on one image were likely to give a substantiative comment on another image. So I would guess that probably most of the CG people give critical advice a fair amount of the time.