Try those examples on Chrome or Android (or probably anything else, but the CSS attributes are all -webkit prefixed so comparing against FF would be silly).
Chrome is just now rolling out GPU acceleration so they might actually work on some platforms but previously they (meaning Chrome and Android) were using a rendering engine called Skia and were dropping out a bunch of the perspective matrix therefore making it strictly affine and preventing any true depth effects.
Try those examples on Chrome or Android (or probably anything else, but the CSS attributes are all -webkit prefixed so comparing against FF would be silly).
Chrome is just now rolling out GPU acceleration so they might actually work on some platforms but previously they (meaning Chrome and Android) were using a rendering engine called Skia and were dropping out a bunch of the perspective matrix therefore making it strictly affine and preventing any true depth effects.