In other words, not everyone will get it on day one, though it goes without saying that manual downloads will also be offered to those who don't want to wait any longer and have the IT knowledge to deal with possible bugs and compatibility issues. (news.softpedia.com)
It even randomizes itself to defend against possible bugs in its own code. (sciencedaily.com)
Stay in the Fast Ring if you want to install all latest builds with new features and many possible bugs (windowsphonearea.com)