Let me start by saying there is absolutely nothing wrong with this mount. It is very nicely made and I appreciate that it's all aluminum.
I think my issue is that I was expecting more out of it than it is capable of, in my very specific situation. This would probably be the perfect solution if: 1. I used the correct size M8 bolt and 2. If It was securely mounted to a threaded metal base.
My plan was to use this, a M6 threaded bolt and washer to mount this in an existing threaded hole somewhere on or near the dash of my vehicle. The issue is the M6 coupled with the washer work to hold this in place but do not keep enough tension on the ball to keep it from rotating with the weight of the mount and arm I'm using. "They make a M6 mounting ball!" you say? True! but it has a completely different, wider base that will not fit where this one does. If they made a M6 one exactly like this one I would've ordered it. As it sits now when my car hits a bump the entire phone/mount goes flopping forwards or backwards depending on what mood it's in. The mount is solid to the ball but the ball can rotate on the smaller-than-designed-for bolt. Really the problem is with my execution of install and not the product but I wish they made this exact mount for M6... just mill the hole smaller?