for bad renders, exposure control in APS works better than gamma IMVHO.  but doing good render is better than having to fix it in APS.  mac and PC standard may now be 2.2, but is user-adjustable (in OS X, maybe in win 7).  back in the old days it was common to see poser 4 renders that were too dark to see the details, because the people were using it in a darkened room at 3 a.m.