Upload & Sell: Off
It's not just about having a dark subject against a bright background. It's about having blocked up shadows in the composition. When I'm exposing to keep the highlights from blowing, that happens quite a bit. Sometimes it's not a big deal and sometimes it is. How often? Often enough.
In the discussions about DR, there seems to be a common misconseption that the D800 only has an advantage if you need to push the shadows more than 4 stops.
Even if Canon files can be pushed up to 4 stops in most cases before a total breakdown, the quality of EXMOR files in the same situation is much cleaner and with much better color fidelity and even detail. If you are used to only Canon files, you don't know what you are missing.
The Canon files do not start showing banding at a certain level that is predictive. When you get it, is dependent on the scene, and with the 5DII we never got to any conclusion about what exactly provoked it.