Personally I will advice getting the 6D, save the money for the lenses... If you are considering FF camera, I hope that you will consider 1DX as well... Price for all about 2.4k++ for 6D then 5D3 4k++ and then 1DX for 7.1k++ (may not be accurate)... Getting the 5D3 will have the af of 1DX but the image quality and the fps is so much different... Getting the 6D and the 5D3, advantage is cheaper, the centre point is definitely better... Wifi and GPS... Personally I like the wifi which I can immediately send picture to my phone and send to friends... 6D when put together with a battery grip, you can still use the 8 way direction to change the af as it is located at the bottom when shooting portrait... Whereas 5D3 the joystick is on the top of the camera, if taking picture with a battery grip in portrait you may have a problem when trying to change the af point.. 5D3 advantage definitely is the different af, the earphone jack... One problem I face with the 6D is that if I use my left eye to take a picture, my nose will hit the live view mode button and it will activate it, secondly if focus is on the corners then maybe you can't reach it due to the lack of af points... 5D3 is between 6D and 1Dx, personally I will go for either the 1Dx if not constraint by the cost factor, else I will get 6D... 5D3 is in the middle so it will still lack some of the things in 1Dx and will have a bit more compare with 6D