One thing that helps is if you can operate it one-handed- the older Canon I had was pretty good for this, the newer smaller Nikon, not so much, and the cell phone is even worse in that respect.

I'd like to have a helmet cam, but don't really want to fool with downloading 18 million billion bytes of extraneous crap to get to the 10 seconds of footage that was really cool, so I haven't bothered.