All depends on how you set the camera up really. There is so much that can be done these days in camera and if you nail it when you hit the tit, then there is so much less post processing to do. I would rate Canon and Nikon on an equal footing here, though we will all have some preferences.
Worth remembering that a lot of wedding photo bods and newspaper shooters rely on this approach as they don't get paid for extra PP time and instead of sitting with Photoshop, could be having a nice cup of tea, or spendig a relaxing ten miutes picking their noses. Their experience counts here. Shooting a thousand or two each week helps them hone the camera settings right down and they are masters at this. For a lot of people here, they will have to work off camera in Photoshop or similar to get the best from a shot, whether it be JPG or RAW format.
One of the biggest drawbacks for a lot of people, is the time that they spend post processing. It certainly didn't appeal to me initially, but now, I find it quite therapeutic - though I wouldn't half mind a bit more time for dunking teabags.
Conan