Wow no way I would spend hundreds of dollars on a dash cam. I have also been looking at these along with head unit for the TJ, at present I probably will be going with this
head unit and this
camera as the head unit allows me to both record and view the dash cam and also allows for the same from the reversing camera. The dash cam is a stand alone unit as well so you don't have to get the head unit and has the usual G sensor for auto recording of sudden changes in velocity as well as auto start and stop when ignition is turned on, it is also nice and small, admittedly it is only 720p but in the end you really don't need more than that.
Whatever camera you decide to go with make sure you can tap the unit to make a separate recording or put some sort of "bookmark" on the recording so you can hit the camera when you see something stupid starting to unfold to make it easy to find it again later.
Best of luck, let us know what you decide on