They are solidly built and do what they are supposed to do. Somehow I initially managed to loosen a clamp a bit - I set the clamp force too much and it didn't open wide enough to be used. A quick message to the support team (super responsive!) who told me to unscrew the adjustment screw all the way and open the clamp all the way. Turning the screw at this point required sharp-jawed pliers, which took more force than I thought the screw could handle, but it worked. Now everything is in order.