In short, my observation was that pictures displayed in photo shop using different display profiles with different gamma in the OS setup look the same in Photoshop (while the user interface elemets are affected by the different gamma settings). In Apples applications (Preview for example) they look differently for different gamma settings. To my impression they look most similar if the display color profile is set to 1.8, which is probably why Apple labels this as the Mac standard and assumes this setting for its applications.