[DJ Urbanovsky]

My perspective:

Out of the autos that I've handled, Microtech or Benchmade have been good to go.

There's also the Speedsafe mechanism, which behaves like an auto, but there's no button to operate. As you open the knife past a certain point, the coil spring kicks in and fires the blade open. No buttons, and legal pretty much everywhere. I'd recommend Zero Tolerance Knives if you want something with this mechanism.

The only OTFs I like are Microtech, but I cannot recommend any OTF because of the complexity of the mechanism, and also the fact that even a piece of paper in front of the blade is enough to foul it and keep it from locking open. Then you've got your blade flopping in and out of the handle until you can grab it and reset it.

Problems I see with side opening autos:

1) Springs break. You've got your coil spring that fires the blade, and you've got the plunger spring. The last thing you want is to go and fire the knife when you really need it and have the spring break. Then you've got a knife that won't stay open, if it even fires at all.

2) Most modern side folders you see these days are going to have a button lock. It's basically a captive plunger with a spring behind it. The problem I have with this is that in order to clear the blade, the plunger has to have a relief turned into it. This turned down area on the plunger shaft can be pretty thin... I've never seen one fail, and under normal use where one is using the knife as a folding knife is designed to be used, it should never be a problem. However, Murphy is a mother... Here in the real world, not something I want on a hard use knife.

3) All mechanisms get dirty just being carried in the pocket, let alone out in the field doing work. On a liner lock, not such a big deal. On an auto where you're relying on that mechanism to fire the knife open, this presents a problem.

Personally, my feelings are that autos are a novelty. I don't want a bunch of fancy gadgetry on any knife that I'm going to use for serious work. The more moving parts you add to the equation, the greater the chance of failure. Less is more. On a folding knife, it needs to have a robust lock with positive engagement, a solid detent, and that's it.

If it's a concern about speed of opening, with a little practice, you can open a knife with a thumb stud just as quickly as you can an auto. If it's a concern with being injured and one handed opening, if a guy still has the capability to fire an auto open, he's got the capability to open a knife with a thumb stud.

YMMV.