I have used a GoPro Hero2 for years and had good success with it, after a brief learning curve regarding what beep signaled what function. I did start having issues with case mount noise though, which I couldn't fix no matter what I did. I have just recently gotten a Session 5, and for what I do (endurance riding, so all out on trail), it's perfect. Being waterproof is also a huge plus, as that removes the need for the case, so no more rattle!
There is no joy equal to that found on the back of a horse.