Ken Rockwell compares 5d3, d800, d800e

5D3 = FUN
D800e = QUALITY

It is all about fun vs. quality.

The Canon is a lot of fun with high quality
The D800e gives the best quality.

Even DPReview's camera reviews say the same thing.
And Ken Rockwell agrees.

If you want the absolute best quality - get the Nikon
If you want more fun when taking photos - get Canon