There must have been no testing at all on this build before it was pushed out, I actually think this build was pushed out by mistake, and maybe we were meant to have received a different one. There are significant issues that were not documented, that couldn't possibly have been missed if any testing at all had taken place. I was aware of several issues pretty much as soon as the installation was complete, the most obvious one being the issue with the iris scanner, then soon after it was apparent that many apps that worked fine before didn't work any longer, though most of the core Microsoft apps still seem to function (for me at least).
Looking forward to the next build and hope it comes quickly in light of the issues with this build.