Fair point! It's hard to assign numbers to perf for something like an entire application - a lot of the wins we found were places where the main screen was locked (causing app un-responsiveness) or where we were able to change the order of some actions to get the app to render quicker.

I'd say the app takes around 2-3x less time to load than when we started our most recent performance quest, largely due to issues we found using hookshot. We did find some performance critical inner loops in our rendering code where we were able to achieve something like 10x speed-ups.

Apple's profiler has significantly lower overhead than hookshot - which makes sense given the relative amounts of information collected. Our app runs noticeably slower when hookshot is enabled, but when it is disabled, hookshot introduces exactly 0 overhead. We only enable it when we're specifically debugging performance issues.