Fred Miranda has posted his review of the Canon EOS-1D X. I always find his reviews easy to read and quite detailed in real world situations.
Overall, the 1D X is a very versatile camera. When you shoot with it, you feel like it can handle anything. Combined with ultra wide-angle lenses, the 1D X captures amazing full frame landscape photos. It does costs more and has less resolution than the Canon 5D Mark III (Read our Canon 5D Mark III vs Nikon D800 review), but you’ll get great dynamic range, less banding, and body that you can take anywhere under any conditions. Sports and action shooters have found a match made in heaven. Only time will tell if other realms of photography will embrace it too.