I look forward to every June when Apple releases the next version of their various operating systems for developers to go through and test. It is a treat for geeks like me. I usually grab a new hard drive and make a backup copy of my current system. I install the new OS and my expectations are that something will break.
This year I'm happy to report that, for the most part, that did not happen. It is extremely unusual for a new OS to NOT break things. A whole lot of things. For me, my work access almost always fails. It usually has something to do with VPN, Java, etc.
That is not to say that bugs don't exist. I've spotted a few. I think Siri is buggy. Logging on to the forums will show you that beta testing causes it's fair share of grief across various configurations, however, my iMac 27″ 2011 is doing just fine. I am using an external cradle to run MacOS Sierra on an external 4TB hard drive. The cradle is connected using Thunderbolt 1.
I have encountered a weird window issue where pressing the minimize button doesn't really minimize. The window acts like it's getting ready to get smaller but it snaps right back in place and then cannot be closed until you quit the application. I'm not sure what is causing this particular issue. I've changed the preference from “scale” to “genie effect” for minimizing windows and so far, I haven't had a problem. It could be just the scale effect itself. Not sure.
So far, I think this beta version is more solid than those I've tested in the past.
Good job, Apple!