Curiously enough, I was talking about this subject only yesterday with my nephew who lives in Wellington NZ but is currently in UK. Having originally booked his flight to UK with Emirates, the first hardware started flying over the Gulf only two hours later and he rebooked Delta to LA and Virgin Atlantic to UK. Knowing what a pain it used to be even for Air NZ passengers simply transiting through LA, I asked how the current experience had been and he said that he could not believe how simple and straightforward it had been.
As regular visitors to the US, my wife and I opted to benefit from the Global Entry scheme a few years ago and cannot believe how much it helps, both with international and domestic national flights in the USA. Indeed, as I mentioned on the very similar thread late last year entitled
Going into USA I have gone from aircraft door to my Chevrolet Suburban ride in as little as 10 minutes after arriving in the USA - in an A380.
Jack