The lockup on my large Apogee is very secure. The full thickness of the lock bar engages the blade tang, and there is zero play to allow the lock to accidentally release. The geometry of the lock is different from the Sebenzas I've seen. It has slightly more tendency to stick, but that makes it even more secure. The Apogee has all the solidity and strength of a Sebenza, I think. Very solid knife, and pretty too.
I agree with Steve about the lock up on the 4.25 Apogee. On that size it is very solid and well done, not too tuff to disengage but tight. On the 3 version the lock is actually tighter, a little tough to unlock but quite acceptable.
On the 3.9 Apogee the lock is not as solid. I believe that this is due to the locking bar cutout being ½ longer that on the 4.25 version, thus allowing more leverage to be applied to the bend in the bar. The bar can actually be bent well past true, or away from the blade past the original plane of the handle scale. This seems to confirm the hypotheses. The bar can be flexed out of the locked position while gripped if you twist and turn it the wrong way. You have to really be trying, but it can be done.