The `1d-x will be very tempting to purchase as an upgrade to my 1D Mark IV, but I'm not sure it's worth it. The images from the 1D Mark IV are amazing. I've enlarged my outdoor images to 40X60 on canvas and they're very high quality. I also prefer the results over the 5D Mark II for portraiture at ISO 100-200. The high ISO is okay, but that is the only improvement that the newer model could offer that could make me get one. I do shoot a fair amount of high ISO events. Waiting long periods of time for the new model released makes it less likely for me to want to update however. I find this rather annoying.