I've written here before about my cycle cam. It's a cheap and cheerful bullet camera which I strap to the top of my helmet. You can find it for sale in many guises, but if it has "Sport DV" written round the lens, then it's the same one, more or less.
However, having now broken two of them, I know it has a couple of weak points. On my first one, the button for turning it on and off failed. They improved the design of that bit on the second one, but knocking it off the shelf onto the floor whilst attached to the charging cable caused the micro USB socket to snap off from the circuit board.
Even without this fragility, the thing was quite irritating: the battery life is only a couple of hours - not a lot if you're cycling 90 minutes a day on your commute. You can swap batteries, but there's no provided means of charging one outside the camera, and every time you do that, the clock gets rest and your videos have the wrong time code on them.
Finally, the footage is literally pretty shaky - no fancy stabilisation in this price bracket.
I've Googled long and hard looking for something a bit diferent, and I liked the sound of the Cycliq Fly 12. Expensive, but much more like it on battery life and robustness, plus higher quality video.
Unfortunately they seem to have exhausted stock everywhere in anticipation of bringing out a new model in November. I've pre-ordered it (at a cost considerably more than I spent on my first bike!), and will let you know if it's any good...