I made my own probe and its very accurate, it is along the same lines as the ones you linked to, ie the 3 rod and ball type. I dont use it for probing and it was never my intention to use it for that, it was made for edge finding and is extremely repeatable, I have it true to less than 0.005mm and it will repeat at less than I can measure. So from that I would say there is no reason to think either of the two above would be any different.
Hood