One problem you'll find is that it is difficult to keep them pointed where you want them to record.
I put one on a head band to try and record. For walking around footage, having it positioned between my ear and temple worked great. But if I was shooting the bow, I had to have it clear back on the back left portion of my head. So if I shot an animal I had to conciously remember to keep my head in it's "shooting position" in order to continue to get footage of the subject/target after the shot.
Then I built a leveling mount so I could attach it to the bow, but that produced poor results because of the vibration and movement upon release. The mount didn't have any vibration reducing parts so that could possibly be improved.
Just realize before you buy one, that getting great footage (shot to impact)is difficult and will take some creativity.
I looked at iKam, but no one ever has their face square to the target so I don't know how someone could ever keep their subject centered.