Upload & Sell: On
I have a 5ds-mk3 coming from CPS as a loan. Since I have a 1DS-mk3, my primary interest will be how much better the live view is and how well it does long exposure high ISO (night shots) compared to the 1DS-mk3.
I expect it to be better in both regards, the real question is if the noise at ISO1600 and 30 seconds are good enough to print. My 1DS-mk3 is not. If the 5D-mk3 is also too noisy to print it answers the question. That is wait for more improvement before doing this sort of photography.
This is one area where the 6D is supposed to be better. If the 5D-mk3 is good enough for 16x24 moonlit shots, I could see springing for it. Otherwise I will either wait for Canon to release a high MP camera and perhaps get a 6D as a second camera. I just sold my 50D.