If you plan to play new, DirectX 12 games in DirectX 12 mode, your choice becomes self evident.
If you plan to use an over the air antenna to record TV, or want to use a CableCard tuner, your software of choice is Windows Media Center, and Windows 10 is out of the question.
Here's an option: Buy Windows 7, upgrade to 10 for free before the end of the month, and have the choice of both licenses.