I have the standard and HD Gopros as well as the VIO and a bullet lens/DVR system. The results with the Gopro are pretty darn good. The down side is editing H264 is really difficult unless you are cruising a high end MAC and some equally expensive software. I have had some luck with Sony Vegas Plat. Pro software for PC. Most folks get around this by converting to a manageable format.
IMHO it is worth the $$, I also use mine for kayaking so the water proof housing is important to me. BTW the Contour HD and the VIO are available with some significant discounts. The chest harness works well and makes the cam operation quite a bit easier. It is not how ever "one size fits all", if you are a clydesdale it may fit tight even with elastic straps.