I have used a number of different digital video cameras to record during flight testing, and just fooling around. I have used the everything proof "hero" cameras on a helicopter flight test. Though they did produce good video, we had several "failures" in that the camera was not recording, and it was quite difficult to know. This resuled in the need to refly, and the operating cost of the helicopter for the extra hour exceeded the value of the camera considerably (I wish they'd bought the better one).
Consider your need to turn it on and off in flight. For reasons below, this may not be advisable anyway. I have never mounted one to my head, always fixed in the cabin, or external as required. I have used remote controls, but they are distracting - see below.
Assuming that your not mounting the camera externally, (which I have on helicopters) you can do just fine with any regular video camera, or even a point and shoot with video capability. If you are going to mount it in the aft cabin, consider occupant safety. In the 9G crash, will it come loose and become a projectile? If you mount it ahead, would it be a visual obstruction, or head strike hazard?
I offer a caution to you that you should ask yourself why you wnat the video. It is fun to keep a record of your flights, and I have a few which I enjoy. If you're going to set the camera going, and ignore it for a normal flight, that's fine. If, on the other hand your purpose is to create some exciting video, please be very careful - you're already distracted by the camera, and now you're flying more dramtically to show off.
The phrase "watch this" while flying has resulted in some very undesirable events. Recording a normal flight is probably fine, making air to air combat or low flying video must be approached with extreme preparation and caution, and is best left to pros...