I have a Polaroid XS100, a Contour +2 (or whatever their highest end model was last year) and a GoPro Hero 3+.
GoPro is by far the best quality video. Much tougher to set up as the camera being level means a level shot. Handy to use the accessory video back (which I don't have) or to use the app which Bluetooth to the camera. I do recommend the wireless remote, as its easy to click and record/stop, see battery life, number of videos recorded and such.
Contour is by far the best overall design, with the rotating lens allowing you to easily mount and level the shot. Contour has also proven to be the most finicky camera, requiring me to download a dedicated software program to do deepest level reformatting of memory cards before it'll work. You learn of this need after many successful videos and the camera continuing to tell you its recording when it suddenly isn't. So after you disappointment of actually not getting the videos you thought you were getting, you need to do a deep reformat to get the camera to recognize the memory card it's never had an issue with until that moment. All that said, the image quality is almost on par with the usual settings used on a GoPro. The GP can, however, record to much high settings, resulting in cinema quality video.
Polaroid is solid bang-for-the-buck. Pretty good video quality, pretty reliable. The camera most likely to be mounted to my crash bar. I used this for a one week tour last summer and every video was recorded reliable, was usable and easily was good enough for online use. Colors are a tad muted overall, compared to video from the other two cameras.