The iPad is certainly the standard, and they're beautifully built (if NOT cheap). As for the Retina, I'd check into how high a resolution it's actually sending over the WiFi. It looks like the image size is relatively limited (which makes a lot of sense - live compressing a beyond HD image and sending it over WiFi would be quite a feat - RED sends full HD with a $13,000 module, but this is $1300 and they throw in a camera with the WiFi transmitter)... I think this is just the Live View image (640x480?), in which case an iPad mini might be a perfect match...