Tip-up knives have been made for a long time too, but when I first started buying modern knives it seemed that most models were tip down. Now I would guess that more models are tip-up. I own and carry both, for me tip-down is faster and more secure. I was carrying a Benchmade 581 today, and it is only available tip-up. The few times I used it today I was aware each time that it is slower and less secure for me to draw it than if it was tip down, but I still like it. If I bought only tip down it would certainly make my EDC rotation a lot smaller.
Some people prefer tip-up so they can use a lanyard. Some people do it so they can put the blade against the seam of their pocket and be more secure. Some people like tip-up because they carry in pockets other than right front, or they have a different kind of right front pocket from what most people have. I read where a lot of people say they like tip up just because they like it, and they can't provide other justification. Other people like tip up carry and admit that it is slower for them.
