[whpalmer4]

And lest you're thinking "oh, that's okay, we can just add the change again" let me caution you that you won't get any sort of notification that one of your changes has been lost! Kind of a bummer when the change that gets lost is the new due date, and you only find out thanks to the customer's irate phone call...

OmniFocus with a single user avoids this problem because most people don't have enough hands to make changes on two devices at once :-)