OK, on Monday, I "bit the bullet" and did a clean, fresh installation of V11.1 of Big Sur onto an APFS-formatted partition on my (new) External Samsung T7 1 TB external SSD, and then migrated files, folders, settings, apps, etc. from my late 2018 Mac Mini's internal SSD. Been testing now fo 2 days, and knock on wood, everything is working fine. Here is a list of applications I have exercised so far:

1. Brave, Firefox, Google Chrome, and Opera all work fine.
2. A new version of Onyx, V3.9.1, compatible with Big Sur, was released yesterday. Installed and ran it, and it works fine.
3. LibreOffice and VueScan work well. I did not download any Canon drivers at all (I have a Canon MX 890 printer/scanner). Just used the printer drivers contained within Big Sur. Again, all is well.
4. VLC, 1 Password, Transmission, Quicken 2017, Klondike Forever, and EasyFind work as expected.
5. Although Thunderbird is not "officially" compatible yet (there was a second beta release of a newer version of Thunderbird on November 24th, and based on what I read, looks very promising), the last stable version is working fine, with just one very, very minor "issue".

I plan on running Big Sur just about every day. Just waiting for Big Sur - compatible versions of SuperDuper! and Tech Tool Pro (suspect the one for Thunderbird will be out soon). On Saturdays, though (as I always do), I'll restart my Mac Mini from its internal SSD (hence its Catalina environment) and proceed with my normal weekly tasks of running Onyx, Tech Tool Pro, and doing 2 SuperDuper! backups to 2 separate external SSDs.

But again, so far, I am pleased. I of course cannot comment on the launching speed of Big Sur, as it is via that external partition on that Samsung T7 (although it is via a connection to one of the USB-C ports on the Mini). But once the start up process completes, Big Sur seems snappy enough, although not much different from Catalina.

Last edited by MartyByrde; 12/16/20 09:51 PM.