The connectors seem to be made out of warm butter. The pins will bend if the connector is inserted at anything other than straight on and the pins will fold over like blades of grass. Otherwise no problems with them.
Without going into a bunch of theory 100ft is way too much for any VGA run. VGA is analog. You will also issues with the communications protocol used to identify the capabilities of the display device in newer displays.
OS's will have trouble recognizing the attached device.
Installing an amplifier at either end of the cable is also ill-advised. One in the middle would be a tolerable but less than optimum design.
VGA is all but gone. I would suggest an HDMI over CAT5/6 or fiber. You can always put a switcher at the front of the HDMI to upconvert.
