Move the pointer above a button and the circle morphs into the button itself, “snapping” into it, enveloping it like an amoeba, causing it to glow in a pleasing way. What this means is the usual precision of a trackpad isn’t required to get exact hits on navigational elements.
I can’t overstate this. The new designed interface is a delight to use, and goes some of the way to understanding why they took so long. The easy way would have been to just have the same old arrow – but instead we got something that fits iOS perfectly.
It is a joy to use.