I recently had them both, side by side. The 5D II just has better IQ. Sharper, less noise, better colors (much better colors).
But...the 7D is the better all around camera. Better controls, feel, etc. I love using the 7D. Also, I could not give up the reach. My 300mm prime is almost 500mm on the 7D, and only 300mm on the 5D II. This was why I sold the 5D II and kept the 24-105 that came with it.
Great camera. I loved it. But for wildlife, the 7D is more useful, even though the 5D II has just plain better IQ for feathers and fur.
If I shot landscape and studio excuslively, I'd still have the 5D II. The 7D is a rugged gunslinger, perfect for wildlfe. The only thing wrong with the 7D is that it should've had 14 megapixels instead of 18.
BTW, I found the 5D II's center AF point more reliable than the 7D's, both in AI servo standard in lowlight condtions with sprinting animals. The 7D's outer focus points were superior to the 5D II.