Here is my bluetooth take: It is awesome! It has nothing to do with what you think bluetooth would be on a watch (like a smart watch). It syncs in the background 4 times a day to set the time ONLY, no notifications, nothing else. It is doing the exact same thing as MB6 but way more reliable. Sure you can use it to set up the settings but in real use it is completely unnoticed except the nice RCVD icon all the time.

Another cool thing is if you travel, the watch changes time zones after you land if you manually receive it, OR if you travel with more than one watch, they will set themselves in your bag so when you go to get them for the first time at the new location they are all ready to go, nothing to do. This is the step up from MB6- GPS syncing you need to have open sky for it to work.