Are we seeing the same differences as in other Apple devices ie warm vs cool screens?
My 2010 Air has a 'cooler' screen tone and looks slightly brighter compared to my 2011 Air,whites look whiter on the 2010 model than on the new 2011 one
It's not free, and if you use the trial version to calibrate your monitor and use their profile, it will then break photoshop, according to that URL...