I already published preliminary analysis of the Retina MacBook Pros display. In short brightness is down a bit - Anandtech
The brightness of the new rMBP is down from the standard screen. Its about the same as dropping 2-3 units of brightness from max on a standard MBP, which is significant.
So the question :
Is there any chance of an extra bit of brightness in one of the yearly updates or will apple stick with this screen exactly as it is until the next 3 year refresh?