You know how people call every kind of facial tissue "Kleenex," even if it's technically from another brand? These days, GoPro is practically synonymous with action cameras. I can't use any other action cam without someone asking me, "Is that a GoPro?
The current gold standard for image quality; Especially the Black edition with higher resolutions and framerates, but at 1080p60 the Silver looks just as good; Audio is very clean and low-light situations are met with low noise; Terrific dynamic range; Sets the bar for sharpness, too.
Battery life; Ho man, battery life; GoPro has never been a leader on this front, but the Hero4 Black-the new flagship-is at the bottom of the barrel; While shooting at 1080p 30fps, it only mustered 97 minutes; Even the Hero3+ managed 115 minutes! Shoot 4K at 30fps and it drops to 70 minutes.