re:
I got my fitbit in yesterday and here's what I've found:
The 8X works virtually flawlessly with the fitbit. All you have to do is open the app, and it auto-syncs. I have read that it is supposed to always be syncing in the background, but that fitbit is having trouble enabling that on Windows Phone. However, I have noticed that every once in a while the Flex will already be synced under the Bluetooth menu on the phone but when I go to the app, it says that it is unable to sync. Luckily, turning Bluetooth off and on fixes it and I already have the Bluetooth toggle in the action center, so I don't ever have to leave the app to fix the problem.
As for my 822 with 8.1 Update One, it doesn't work at all. I know that it is because it doesn't have Cyan, but I was hoping that by some divine interference, my phone would be different from all of the others and it would just work, haha. My 822 gets a lot better reception and battery life where I live, so I hate having to stay on the 8X (which I normally only use for media) all of the time, but it looks like it will be that way until Verizon releases Cyan for its phones.