[aprendo]

Scrolling is buttery-smooth on most websites, less so as complexity ramps up. (Some particularly complex Facebook pages, for example, have minor stutters, i.e. dropped animation frames.) Still, it’s minor stutters even on those.

That’s with Mountain Lion. Lion was markedly different.

[yuhong]

Fortunately Mountain Lion was announced at the same time as the rMBP, and it was announced even back then that rMBP owners will get Mountain Lion for free.