where I live, the 5D III is currently available starting at Euro 2600,- [incl. 20% VAT]
Nikon D800 is starting at Euro 2075,- [incl. 20% VAT]
As a matter of principle I will NOT buy the 5D III, as long as it costs even 1 cent more than a D800.
Most likely I'll get a Sony A7R next year, once good non-Zeiss lenses are available at reasonable cost. :-)