"... every iMac display is individually color-calibrated using state-of-the-art spectroradiometers..."
They are incredibly thin as well. More here.
Another spec bump of interest to photographers is that 27" iMacs can now have up to 32GB of RAM: as much as the dual processor Mac Pros, still not up to the 64GB maximum of quad-core Pros.
Also, the "Fusion Drive" combination of 128GB SSD with 1TB or 3TB HDD, with the OS automatically moving most often used software to the SSD for faster operation, is intriguing. Swapping Aperture to the SSD while relegating iPhoto to HDD was the example mentioned.
Is it time for another round of photographers with Mac Pros choosing between
- an iMac
- waiting for the promised 2013 update of the Mac Pro
- changing to Windows (or Linux?!)
P. S. The thinness is more a visual than a practical change, allowed by eliminating the internal optical drive: it is mostly a thinner edge but still almost as thick in the middle of the body, and as "deep" on the desk.