This was very easy to use, but DO NOT FORCE the pins.  If you need to force them, then you are not on target, and you WILL bend the pins.  The pins are necessarily very narrow diameter, so they bend easily under the force of the screw.  If you feel more than a token resistance, then you most likely are off target.

The only real complaint I have is that the height base rotates (and so adjusts) too easily.  It's quite loose, and so it ends up slipping just by virtue of handling the device.  Other than that, it was fairly simple and easy to use.