Interestingly, one of Dinan's selling points is that it retains the nylon pivot ball and bushing instead of having metal components, whereas one of UUC's selling points is that it foregoes the nylon ball and bushing for a ss ball and ball bearing.
Pure speculation, but perhaps Dinan's is smoother (more buttery?) at the expense of some precision, while the UUC's is more precise at the expense of some notchiness?