The tip up/tip down carry issue was brought home to me after getting my BM551 and only having tip up carry available on it. Prior to that, all my knives were tip down carry and... that is what seems to be indelibly ingrained in my brain and muscle memory. I find it far more elegant to simply pinch the knife, draw and let it rotate into the palm (using your pinch point as a hinge) before releasing the blade. I know technique can be altered for each carry mode but... in the heat of the moment, I don't want any confusion over my draw and deployment. I have recently changed all my knives over to tip up carry to match the Grippie and standardize but... it is still less instinctive to me to have to add the extra move of positioning the handle, lengthwise, in my palm before deploying the blade. Safety aside, tip down just seems to be more natural and fewer motions for me. Your thumb is already at the right end of the knife for thumbstud engagement on your first grip of the knife, not second.
After some months of converting, I find that tip up is still giving me fits whenever I don't take a second to think about it first... Just another opinion amongst many... :yawn: