My guess is that the Cinema Display will - as the 24" iMac and the older CinemaDisplays - not have a cheap TN panel but a more expensiv (and more vibrant, color rich) (M)VA Panel where LCD screens with VA panels are at least as expensive, most others are acutually more expensive and for VA panels 14ms is quite good.
If I am not mistaken the 24" White iMac had an IPS, the Al 24" iMac did not.