In Chrome 19 on Linux the linked demo does not exhibit any changes in aliasing when clicking the boxes. Does anyone experience different results in Chrome on Windows or OS X, or perhaps Safari?
(I write "attempts" because the rules are complicated: http://neugierig.org/software/chromium/fonts/ )
I checked on my iPhone 4S and when I zoom in I can see a difference (that I might be missing on my desktop). It is incredibly subtle.