Sadly, it’s awful for me.
I am experiencing frequent freezes on my Retina iMac. Sometimes out of the blue, often when changing between running apps. They can last between a few seconds and more than a minute, and a few times a day the system will not recover and restart or shut down.
Kernel panic reports mention different watchdog processes as the possible cause.
The usual cleanups did not help. Maybe a clean system install would, but currently I shy that solution as long as I don’t find confirmation on its success.