I want to know what separates the Hero 5 Black from the 4+ Black???
Here's some other stuff: voice control, video stabilization, a RAW photo format, automatic GPS tagging, and automatic uploading to the new GoPro Plus cloud service.
The fact that it's waterproof is a plus even though you'll still need the Super Suit for diving. My GP4 Silver housing cracked at the base and lightly flooded and destroyed the GP4 on my second dive of the day. My best guess is it was crushed by a larger camera in the rinse tank. Not sure how the GPS will work underwater.