The HEST 2.0 was perhaps the first heavy-duty folder I owned. It was a VERY heavy-duty knife with a blade thickness of 0.190", which is the same thickness as a Strider SMF. My HEST had a sticky lock, which seemed rather common "back then" a year or two ago, although various owners reported that it "broke in" after a bit of use and was fine. I'm a casual user, which means I seldom deploy my blade and then not for anything serious...thank goodness. I wasn't fond of the rotating thingie that converted it to a "fixed" blade. A decent lock shouldn't fail when deployed under normal circumstances, and if you're using it for something that unholy, that you should be using a gun and you should be running backwards. The HEST is a darned good SMALL footprint pry-bar, and I don't mean to make light of it. It's easily carried in a pocket.
The ZT 0566 has not YET made it to my home, but it will. I've had many ZT's, and they are all great. However, many of them are too large for my personal use and I got rid of them soon, such as the 56x series folders. I've had a bunch of 0350's in various configuration, and they're all great. Heck, you can even find one in M390...an outstanding blade-steel. I have a nice NIB 0550, generation 2, and just purchased two tactical collab models 0360. The 0566 should be a good size and I'm anxious to try it out pretty soon.
sonnydaze