So an attempt at a brief summary of (the non-thread-priorities portion of) her post:

The Android model of providing rendering isolation between apps/windows has limited hw acceleration of window contents rendering, which is a cause of some of Android's lagginess. That iOS forgoes this isolation and achieves better responsiveness is a reflection of a different security philosophy.

If this is an accurate summary, it's an interesting example of how platform design is wicked problem with complex interactions between concerns that you might expect to be orthogonal.