I have done the comparison as well. Comparing the 7d to the 5d II image cropped to match, the amount of improvement you gain with the 7d is marginal. If you have no PP skills it is non existent as the 5d II will be better. To make the 7d file marginally better requires more processing than the 5d II. The difference is not enough to matter.
The difference that does matter is the AF system of the 7D and the high frame rate which makes it a better wildlife camera.
I'd take the 7D over the 5DII for birds/wildlife/sports. But compared to the 7D, the 5DIII has better AF, much better high ISO M, and gives up just 2 fps.
When I got my 5DII, I kept my 7D for birds/wildlife. After getting the 1D X, I sold the 5DII. Now, I'm not sure I will keep the 7D...the IQ is no where near the 7D, and with the new 1D X firmware I can now AF at 1200mm...
Outside of a backup body, why keep the 7D?