While previously pressing it would have initiated the ejection of the CD/DVD or opening the tray of the optical drive, now one needs to maintain the key down for at least half a second to get the operation started.
If this modified feature is not described in Apple TechNote, it is a good improvement as it will prevent most of the unexpected media ejection taking place by pressing the ejection key inappropriately.
[update]
As reported on our forum by dbcanada it also affects other key combinations:
Also affected is the Control-Eject keyboard shortcut that brings up the Restart/Sleep/Cancel/Shutdown menu. With OS X 10.4.9 you have to press the Eject key a little longer than you did previously.
