I am aware that there's a problem with using Crossfire with 16.12.1. I'm fine with that as I'm not currently playing anything that needs it and have no plans to in the near future.
However, I can't turn Crossfire off with the Crimson software, it crashes if I try. I get a "Radeon Settings Host Application has stopped working" error every time I try to turn it off in the driver settings.
This is something that people should be aware of if they decide to jump over and have a multi-gpu rig thinking they'll just turn it off until a hotfix is released.
I had to go into my case and remove the bridge to get it to disable Crossfire with 16.12.1 installed. That's not terribly difficult to do, but not everyone will think of that after finding out that the new Crimson drivers break Crossfire.
I know I could have just rolled back, but that would have been an even bigger pain to deal with as I'd have to dig up or redownload DUU, rip everything out, and reinstall the old driver. It was just simpler to take off the bridge for now as I'm not really using Crossfire for anything currently anyway.