I think if you go for one of the main brands, you can't really go wrong. It depends on where are you going to place the camera and what features you really like and those that you can live without.
I wanted my primary camera on my helmet and didn't like the wide frontal area of the GoPro.
I wanted one which had a rotating lens, to avoid the slanted horizon you see on some videos, so that ruled out Sony.
I needed to be able to replace batteries on longer rides, so the Replay XD was out.
So for me it was down to Contour and Drift. Now it was much easier for me to compare the prices and features of just 2 cameras.
At the time, Contour looked like it might be going out of business. Would getting parts or service be a problem?
The Drift Ghost came with everything I needed in one box; remote control, microphone, wifi is useful when setting up camera angles and viewing video, and the
screen makes it easy to view or delete video or change settings while I'm out riding. You can also record while powering it from the 12V socket.
When I wanted a 2nd camera, this time to put on the bike, mainly for facing towards me so I can add the picture-in-picture effect to my videos, I didn't need the capabilities of the Ghost and I
didn't want to spend so much money on a secondary camera, so I found a new Drift 720 for a quarter of the price of a Ghost.
So get the camera that will best suit your needs and your budget. But start be eliminating cameras that lack features you consider important.