I'm using the Alpha. Never had an issue until today.
I go to edit a post (because I was attempting the Twenty Fourteen theme, but that's a whole other complaint), and I get a completely blank post edit area. I tried in Chrome (recent version) and Firefox (recent, as well) and both of them have the issues. I can't click on the text tab, either, and view that way.
Not sure if it was the update, but it was working earlier, and a 3.8 installation on another site isn't having any issues.
Here's a screenshot of what I'm seeing.