I installed macOS Big Sur Developer Beta 4. The installation went fine. As far as I can tell, there are no new features in this Beta. It seems to run fine, it is very snappy. Most of my main workflow Apps work well so far. I am sure Big Sur will be ready for a September release. By the way, if you wanted to run the Beta, then this article explains how to sign up and install it. Just don’t install it on your main workflow Mac. I have mine installed on an external hard drive.