Ed,... On the Windows side, you have to buy tool like PC LapLink's PCMover if you need to move Win 7 users to Win 10. (I see what you did there Microsoft!)
When you use a tool like PCMover on Windows, the end result is far from perfect. Every time I have to do a Windows migration, I pray for something like Migration Assistant on Windows.
While, yes, I’d like a little more granularity, I can use Migration Assistant, and the new system just works. No questions about if a required piece didn’t get transferred, or if it was, did it overwrite a newer version required for another application.
Sometimes simple is the best UX.