Mac OS Sierra - Caution!

Apple has released Mac OS Sierra (version 10.12), and folks are asking questions!

1. Should I upgrade?
2. Are there incompatibilities with some of the apps I use?
3. How do I un-upgrade?

Here is the answer key:

1. Be cautious! Read the answer to question 2 before upgrading.
2. I've been running it a couple of weeks, and find it mostly good. In our configuration we have found two incompatibilities so far: Bria (our VoIP softphone app) and Thirtyseven4 (our anti-malware app). So, to answer question 2, check with the developer of your must-have apps to be sure there are no incompatibility issues before proceeding.
3. Apple calls it a rollback, and another common term is downgrade. There are steps to do this that work; I recommend Googling downgrade sierra to el capitan to get the steps.

 I'll post updates as I have them.