In reply to Bobling:
Personally I'm not a fan of headcams - I find the not-very-steady-cam video they produce both irritating and literally nauseating (i.e it makes me feel sick). Handlebar mounting is not quite so bad, but still tends to have an annoying wobble caused by the continuous small steering corrections that are pretty much unavoidable on a pushbike. For that reason I've given up on my Cycliq Fly12 too (plus the fact that the integrated light was decidedly unfriendly to other road users - on road I now use a light that's compliant with the German StVZO standard which mandates a clear horizontal cut-off, like dipped car headlights). Until someone comes out with a decently priced bodycam I tend to use my el cheapo GoPro knock-off* on a Decathlon chest mount (in fact Decathlon do a couple of cheap GoPro clones as well).
However, if you feel you have to go down the headcam route then have a look at the action cam reviews on Techmoan:
http://www.techmoan.com/blog/category/action-cameras
His current favourite headcam is the Drift Innovation Ghost X.
Top tip: disable sound recording. Unless you are confident in your ability to control your language in stressful situations, your sarcastic/annoyed/aggressive remarks to idiot motorists can be used as an excuse not to take action against the person who tried to kill you. Shouting rude things at someone who's almost driven in to you gets labelled as "There was clearly fault on both sides", or "You were antagonising them" if they become physically violent.
* This one, in fact: http://www.techmoan.com/blog/2014/2/3/the-sj4000-action-camera-review.html