I have never been that blown away from stock footage taken from a Go Pro... colors and exposure have always needed balancing in Adobe to make the colors pop and to correct the exposure to give you that more "professional" look, however there is a reason for that...
It is better to have it that way then over saturated stock footage. Therefore the Go Pro is better for a professional environment, you have near to no pre processed colors from the CCD which makes it easier to work with in post production and maximizes the detail (and it is the DETAIL that you want) and with the new Hero 5 you have control over the exposure as well with some degree of image stabilization too.
If you want good usable footage without too much or Zero post editing work.. then probably the cheaper ones will do, they always whack the saturation up to compensate for the lack in quality/sensitivity of the CCD which also on the face of it makes the straight up non edited footage much brighter in a back to back comparison and therefore "better".
However in the real world a camera with a cheaper CCD and running a higher saturation also provides massive losses in detail, Which in turn makes it a nightmare for working on it in post production in a pro enviroment.
If you are doing footage professionally then I would say the GoPro is still the one to have due to its non processed footage. You can also make the quality/detail of the Go pro footage even higher by switching on GoPro's Pro Tune feature (which some of the cameras have) which increases the data rate of the footage etc, that said the stock footage of a Go Pro will actually look better than when its on Pro Tune mode but the Pro Tune DATA will be much better for post editing, which in turn makes the Pro Tune footage amazing once post edited (which is what you end up seeing in all the Go Pro adverts which is post edited pro tune work).
I would say if you are going to be filimg a track day, going on holiday, diving, using it for fun stuff then get a cheap one.
If you plan to work with it professionally then get a Go Pro as there is much more to it...