I know the different specification for both cameras. For may personal use, I think the speed shooter and the "sports" focusing system is not a reason to spend close to double if I am really don't get spacial benefits for my job. In othe hand the dedicated DIGI4 for the metering system and the ISO range looks incredible better than in the 5D Mark III.
Also the number of life shoots (I think 150.000 VS 400.000) of course!
I am asking because I really want that someone that know more than me give me a tip. Sorry if the question is very stupid, but I never had a 1D, only I had the 5D and the 5D Mark II and I am looking advices for other colleagues.
Thanks in any case for your fast response!