For this D800 vs. 5D Mark III article I decided to summarize the results from the comparison table at the top of the page, so it’s easier to see the differences.
The superior feature is highlighted in green. You can see the full specification comparison below the summary table. Have a look and tell me which features you think are more important for you?

Canon announced their new “enthusiast” level full frame camera –  EOS 5D Mark III on March 2, 2012. It is the replacement of the previous model 5D Mark II and although there are no many new features, Canon have listened to their customers and “fixed” the major things they were criticized for – auto-focus, weather sealing, shooting frame rate, etc.
I won’t describe the detailed characteristics of this camera in details as you can see those at so many places online.