I'll answer... Jno, despite taking a month :) (i don't come here often)
The GoPro doesn't offer anything tangibly more than several other "action cameras" in any way despite costing 4-5 times as much.
OK, it can do 4k in higher frame rates than a lot of other cameras.... but nearly nobody can edit, process or view 4k, 1080p is fine.
It does do slow-mo better than most... if you want it, but if you want slow-mo then there are better options too. (my phone matches the go-pro on that!)
The go-pro isn't a bad camera, but they are trading on being the first well known one and charging 3-4 times as much as cameras that are 90% as good.
(I say this despite working with them!!)