The highlight feature is actually interesting.
"The daddy of the family, Hero4 Black, has two key features that fans of GoPro have been waiting for since the Hero3: 4K video recording at 30 fps, and 1080p now at 120 fps (you can also grab 2.7K at 50 fps!). The Hero3 did 4K, but only at 15fps, making the feature less useful for professional projects. The Hero3+ didn't improve on that (and perhaps suggests why that wasn't branded the Hero4). But, it looks like GoPro figured out how to deliver full 30 fps 4K without ravaging the battery (more on that battery later). Other new features include a "highlight tag" which allows you to mark a key moment in your video via the WiFi button on the side. If you're shooting hours of video at a time, this will make finding those sweet airs/best waves much easier once you import the video into GoPro's Studio software."
http://www.engadget.com/2014/09/29/gopr ... 4k-camera/