we have a GoPro4 Silver. It is great for what it does, We bought it when they first came out and really didn't know what we wanted (and didn't have time to ask around or do any research) The blue tooth transfer is very convenient when you get back to the room to just download photos and video to another device, the waterproof case is solid, floats on the surface, and has not failed us in any way,and it takes great photos and videos....but...
I wish I would have bought one of the underwater cameras with ability to see your shot immediately and see what you are taking the picture/video of. also, on our last trip, my finger hit the button that switched it from single shot to video and I missed pictures of a large green moray swimming literally with me for 50 or 60 yards. When we downloaded the photos, I was clicking the shudder button so fast, the video never had chance to start filming. There may be ways to lock the setting so a finger slip cant cause that to happen, but I haven't found it or had the urge to look for it.
Go Pros are great for what they are, but I wish I had immediate feedback on my shot, the ability to zoom in or out, easier settings, and a bigger screen.
Jay