ive run Sierra beta for a while now but, you know, I just don't care about it. 10.11.6 is pretty stable so I'm simply not seeing a compelling reason to upgrade. 10.11.6 should be good for another couple of years with security updates. I'm likely hedging my bets to see what 10.13 and 10.14 bring to the table. Perhaps the expectation for OS X upgrades is too intense as recent years have shown a diminishing upgrade value. That's perhaps just a sign of a mature OS.