Update March 1, 2008: More on LED backlighting on the MacBook Pro 15.4″
Probably the nicest feature introduced on the Santa Rosa MacBook Pro’s is the LED backlit screens. The reason? Instant brightness adjustment (which Leopard now fades in for that ultra smooth user experience…).
When waking up a dozing Santa Rosa the screen (in Tiger) gets to full brightness immediately. In Leopard it fades into the preset brightness in a couple seconds. This is really noticeable when using the lappy attached to a second external LCD which uses conventional fluroscent tube backlighting, which takes about 5 or so minutes to get to normal operating brightness.
Over the longterm screen brightness should stay quite a bit more constant as well. If you’ve ever compared laptop screens from the same model but from different ages, side by side you’ll notice the older laptop screen is not as bright as the fluro tube gets dimmer as it ages. Not too much of an issue as you can continue to increase brightness (unless you’re a max brightness kinda guy/gal already).
And finally, LEDs use less energy to produce the same lumens as a tube so you get a bit longer battery life as well.