So, here is a review and a bunch of tests on dynamic range, low light, focus, and video between these cameras:
http://www.learningcameras.com/reviews/4-dslrs/92-canon-6d-vs-5d-mark-iii
Canon 6D Vs. 5D Mark III Hands On Review
Interestingly enough the video on the 6D looked much sharper than the 5D. However, while my video didn't have much Moire in it, other tests are showing this is a huge issue in the 6D and not so much in the 5D. Canon must have removed something to make the 6D sharper that no longer defends against Moire.
http://www.learningcameras.com/reviews/4-dslrs/92-canon-6d-vs-5d-mark-iii
Canon 6D Vs. 5D Mark III Hands On Review
Interestingly enough the video on the 6D looked much sharper than the 5D. However, while my video didn't have much Moire in it, other tests are showing this is a huge issue in the 6D and not so much in the 5D. Canon must have removed something to make the 6D sharper that no longer defends against Moire.