I don't know if the issue is with the new Magic Keyboards, mice and trackpads or with the devices themselves but the bluetooth on my iMac and now my Mac Pro have been absolute crap for several months now. The keyboard will cut out and sometime not even register the key up event and end up with something like aaaaaaaaaaaaaa or go on a delete spree until the powered off keyboard finally disconnects. The mice and trackpads simply connect and then disconnect several times through out the day. I haven't been able to isolate it because multiple computers with their own set of keyboards are doing it. Is there just a major bug in Apple's bluetooth implementation in Sierra or am I running into interference with too many wireless devices in my office? Does anyone have any experience with this issue?