I only recently got into ZTs, but I have two now and have already worked them a bit. I think I've had my 0550 for about a week and a half, and I've already put it through probably... 30 zip ties, 100 feet of cardboard, plastic wrap, blister packaging, paper, etc. While using it to bust zip ties off packing crates, I realized it was fastest to press the blade across the tie and whack the back of the blade to basically make a single pop baton. The blade blew through the thick ties we use and bit into the plastic below, time after time.
I am still on the factory edge, with no touch up required yet. It still slices great. No, it's not taking paper quite as laser-clean as it did out of box, but it is damn close. My Persistence would have required multiple touch ups along the way. Sure, it was easy to maintain it for work, but the 0550's CPM S35VN is ready to rock and roll even after lots of work. I will not find myself holding a poor working edge with this blade on me.
My 0566 has been with me a couple weeks longer and has done even more work. That's my usual work day carry lately. Still on the factory edge. Still slicing paper pretty cleanly. The Elmax has been awesome.
Ergonomically, I prefer the 0550 for extended use (that fat handle is great in use!), but they are both fantastic in hand.
You should note that I haven't bothered to discuss lock strength, opening speed, or how smooth the action is. The reason is simple: these things have not mattered at all in use. What I care about is where the rubber really hits the road-- how the blade interacts with what it is going through, and how the handle helps or hurts my ability to work with it.
For my purposes, these ZTs are living up to their reputation and then some. The Elmax controversy has not been reflected in my experience at all. On the contrary, I love it so far.
Would I buy more? Sure... The 0770cf would be a great 'going out' blade. The 0801 is an aesthetic miss with me in it's original form, but the washed versions are sexy beasts. I will own an 0562, though I wish it had a lanyard hole.
Oh... and KAI is 2 miles from my house in a Tualatin, OR, so it doesn't suck to be supporting local business
