We prob. wont know for sure until it is released but keep in mind that the EX1R does have 1/2 inch as opposed to 1/3 inch chips in the NX5U. So if you wanted identical images you would prob. want to go with the EX1R.
Having used the PMW-EX1 and HVR-Z7 (should be roughly the same sensor as the NX5) together on shoots I can say for many uses you won't really see a big enough difference.
