So... I finally did a pretty exhaustive comparison of my new hi-res PB15 with the old Al15 at work (1.5Ghz, pre-scrolling trackpad, w/10.3 on it).
For what they are worth, here are my conclusions:
The new display is NOT brighter than the old.
The old display has richer colour saturation - noticebale on oranges and reds particularly, and thus actually looks brighter when displaying colours/images.
The new display has much whiter whites. This gives the new PB an illusion of increased brightness - but to me, it is only in the whites, not the colours. The old PB whites remind me a lot of my iMacG4 17" screen, which has a much warmer tone.
Try as I might with various colour-sync profiles, I cannot get the new PB15 to mimic the old in terms of colour saturation and the off-white tint (which is easier on my eyes). Changing the whitepoint to D50-60 deoesn't have the same affect. And this is with the old PB15 set up on the default "Color LCD" !
The old PB15 displays NONE of the interference artifacts (wavy or static lines in solid oranges/reds/pale blue windows of mail, iTunes) that the new one does.
And of course - the old display does not have the horizontal pixel banding either.
But, then ofcourse: The new PB has more pixels - its selling point (and one of the reasons I bought it without an additional external display).
So, to my point Wildcard

- I too, find the new display to be fatiguing after long periods. I find myself turning the brightness down as far as possible, and half the time frequent Apple-Option-CTRL-8 to invert the whole display to white on black (as I am now). I also have installed tinker tool so that I can turn off font smoothing right up to 16point or more. This really helped my eyes, yet it seems perverse - the higher res should have made antialiasing MORE pleasant surely...?
wildcard said:
While the lines on my replacement aren't nearly as bad, I continue to suffer from headaches and other problems when using the Powerbook for more than a few hours at a time. I'm not sure if my eyes just don't like the new resolution, some flicker that I'm sensitive to that others aren't, or what. I have a call with Customer Relations tomorrow to discuss my options for getting a refund.