yep, got one. takes a while to suss out the perfect position and angle of dangle but you can get great footage. i got a cordless one initially but the picture kept breaking up so i got one with a cable and now i get great footage, madison do one that plugs straight into you camcorder,heard good reports of it. got mine off a mate who knows abit about electronics and the guy in my local jessops is really cool and helped me to set it up coz i get most of my stuff from them, but they didn't do the helmet cams.
i found that forward view off the helmet gets dull though, under the seat is good, you see what the bikes doing and see how much you lean.(your head tends to stay up right as you corner, so looks less extreme) also chainstay mounted is good, forward and back. makesure you get a wide angle set up though, it gives the impression of speed more by focusing on what your looking at so giving a more blurred edge so its more like your eyes would see it.
hope that helps
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