I have used it. It didn't work on the plane I tried to migrate over, which was the Captain Sim 777. The tool was advertised as the Migration Tool for 'CaptSim' specifically, and then CaptSim stated that wasn't 'their' tool and that the 777 wasn't to be used in P3D.
That really let me down. I still have it though, hoping they will change their minds. Perhaps I'll just make my own 777 for P3D.
But, back to the migration tool. Somehow it changes the Registry, the EXE files in the sims and when you run the installer, it will appear to load into P3D. But, I heard someone say that you need to have the tool 'on' when running things that are migrated over, which makes me think it links to things in FSX.
Bottom line, I still do not fully understand how the tool works. It has an 'on' mode and 'off' mode, and states that some things require it to be active when the sim is running, and that you must use it when installing things that refuse to install into anything except the FSX folder.
That's all I know about it. I am still puzzled by it. I think I did get it to install something else fine, but haven't used it since.
Bill