I was quite surprised to find just how much force is required to activate on the ultratech. After a couple of times my thumb is a little sore....no worries about activating in pocket! From the older ones I fooled around with, they seemed to be a bit less stiff, but they were approximately 3-4 years old and used regularly by my buddy in Texas. But when I say "less stiff", it wasn't by much, perhaps easier to close is all. I like it a lot, and it really solves the problem I had with a spring assisted openers I was carrying on my weak side. Even with practice, I found it difficult to grip and deploy quickly enough to use effectively. The OTF works extremely well for that use. As soon as I pull it out of my weak side pocket, my hand grips it perfectly, and the switch falls right under my thumb, ready to be activated. The one thing I'm curious about is, does the extension of the blade have enough force to pierce something like a belly? It comes out with authority, and I can see being in a ground and pound situation where you're on the losing end, and pressing the end of the blade against your assailant's belly and activating the blade. I haven't been able to find much online regarding this particular use.