What I am worrying is the video will keep shaking while I am doing tricks and it will become difficult to watch.
Any body mounted camera, GoPro or otherwise, is going to be moving around a lot when flying. I've tried both head and chest mounts and.... no. For me it produces something quite difficult to watch for long periods. And no amount of stabilising post-production trickery will eliminate this. There are some VF entries that illustrate this.
I don't care for the fisheye look of the videos myself.
With GoPro's Hero3 you now get a choice of views for most modes so you can choose to remove the fisheye.
However, the GoPro is a useful and tough camera. Get a small tripod for kite videos though.