When attempting to copy files that already exist in the destination folder, Vista gives you these options:
This dialog has a lot of explanatory text. And to my eye the actions--what you are supposed to click--are not strongly distinguished from the other text (a problem of visual hierarchy). I think the presentation is a case of a bit too much information that serves complicate the choice.
Compare the above to this Mac OS X dialog for the same situation:
Here, at a glance, I can see there are two choices: stop and replace. The button treatment of the actions makes them pop out from the other elements of the dialog.
I suspect if we were to do A/B testing of these solutions, there would be significantly lower task times associated with the Mac OS X presentation when compared to the Vista approach.
