[ajross]

You want to test software on a device that doesn't exist in the market yet, but you don't want to build it yourself? The time you'll spend figuring out whatever emulator you're going to use is far longer than the time it takes to build x264 from a developer branch...

[DarkShikari]

In all fairness, Intel's emulator is incredibly easy to use; it literally works like this:

sde -- ./myprogram myargs

instead of

./myprogram myargs

There's also probably a decent number of people at this point who have prerelease CPUs; they tend to breed quite explosively in the month or two before the official release.