Last year, Apple announced that the first one million people who applied for the OS X public betas would get into the program, but it doesn’t seem as if those numbers were ever confirmed, or anyone was actually blocked from signing up. Regardless, iOS was eventually added to the mix, ahead of Apple’s decision to merge all developer programs into one.
The long and short of it is that anyone who is interested in getting iOS and OS X betas can sign up, download copies and install them. It’s sort of like the Windows Insider program, where, if you are still taking a breath, you can apply and be assured of getting the final version when it’s released.
But that doesn’t mean you should jump onboard with Apple’s forthcoming operating systems. Remember that they are, in their own ways, supremely buggy, and performance may not quite what you expect, or what Apple has promised. Take OS X El Capitan and Apple’s claim that apps will launch up to 40% faster, and that you’ll be able to switch from one to another twice as fast. Apple says “up to,” and don’t expect to be able to gauge final performance until the release version is installed.