I've been playing with the macOS Big Sur betas on an external drive from the moment the first one became available. Much like the graphic overhaul that was done with Sierra, Big Sur is redesigning the user interface from the ground up. The difference this time is that there is no Jony Ive at the helm, and the results are—in my humble opinion—butt ugly. Early on I knew there would be inconsistencies and things that just didn't look right, but considering we're now up to Beta 9, these bits of flotsam and jetsam should've been swept away.
Sadly, there have not been, and the once-elegant Mac UI is starting to look like it was designed by disparate groups of first year graphic design students who don't like each other, much less speak to each other.
There are certain things about the new OS that I do like. Certain little tweaks that were mirrored on iOS that I am looking forward to putting into use on my Mac. Unfortunately, since the external drive I load these betas on isn't as large as the drive in the Mac, I can't recreate my profile and transfer all my data to test out in a real world environment.
So yesterday afternoon I decided to throw caution to the wind. I cloned my main hard drive and installed the latest beta directly on my laptop.
All I can say is I'm glad I made that backup.
I didn't experience any issues updating the OS, but when I logged in and things started loading, the screen started flashing and wouldn't stop for nearly a minute. This was not normal, and wasn't anything I'd experienced either while running the OS off an external drive or booting into a different account on the Mac. I knew it be something incompatible in my profile that was trying to load on startup, so I started pulling items one by one but to no avail. When I finally removed everything that was attempting to load on startup and the flashing persisted, I gave up. I completely wiped and drive and restored the cloned image I'd made earlier.
I may try this exercise again at some point, either by doing a virgin install of the OS and restoring my data through Migration Assistant, or with a virgin install, manually installing apps, and transferring my data by hand. But not today. Or even tomorrow.