I have both and find them equally strong and secure. I do find the BM Axis to be smoother and quicker into action. The main differences are as follow: Axis bar slides over the tang behind the pivot point and the Ultra slides forward into a notch in front of the pivot pin. So when direct force is applied to the blade's spine, the tang is push up against the Axis bar, and with the Ultra the metal from the spine portion is actually pushing down on the locking bar. Cold Steel claims the Ultra to be stronger due to the fact theat the locking bar is completely surrounded by metal. A half moon channel is cut completely through the blade tang. I would trust the Ultra lock further than I would the Axis due to the fact that it's Cold Steel and they put so much emphasis on lock strengh. My words don't mean much because I have never personnally tested either to their breaking limits. They are both excellant IMHO.
