At the end of the project, I Sort by Checkmark Status to make sure I didn't miss anything.
I had run into a similar problem a couple of years ago, when a coworker and I were both making checkmarks in the same PDF document. I had no easy way to see what was Completed (checked off), and what was yet to be completed (unchecked). We had to resort to "Sort by Status by Person."
Sort by Status by Person, in theory (I suppose) could be useful. If people in a workgroup had a certain selection of tasks to do, and there was never any overlap in job function between workers, and you just want to which co-worker has completed which tasks, then Sort by Status by Person would be useful. But I never need to know who has completed which tasks. Being ever efficiency-minded, I just want to know whether or not the tasks are all complete. That's why I use "Sort by Checkmark Status." And besides, the "Set Status" takes about 4 clicks, but making a checkmark only takes one click. One click sounds better to me than four clicks.
Well, a few months ago, I started using Acrobat Shared Review with one of my clients. While working on a shared review PDF one day on my laptop, I discovered that I could see checkmarks that I made from my desktop. This has to do with the fact that Acrobat on both my laptop and my desktop were set up to have the same user ID in Acrobat.com.
Quick confession, a couple of years ago when I first discovered the limitations of Sort by Checkmark Status when used in a workgroup, I sent a fairly harsh feature request to the nice people at Adobe, chastising them for not warning me that I wouldn't be able to see checkmarks that other users made...Well, it turns out the Acrobat team actually provided a such a warning the very first time I made a checkmark. And in my haste, I clicked "Don't Show Again." And so, to whoever got my harshly worded feature request riddled with exclamation points, I am sorry.