Hey Unsub, I did not want to hijack a thread so I'll post this as a new thread.

I am a Spyderco collector too but I think I can give you a fair assessment of the Spyderco knives with zdp-189 steel.

First, they are great knives for EDC. Spyderco workmanship and quality is appreciated and proven to many, many collectors and non collectors.

Now the zdp steel is a mixed blessing for me. The blades come razor sharp and if you use them for routine light to medium cutting, you will rarely have to sharpen them and when you do they are easily touched up with a sharpmaker or similar ceramic stick type sharpener. Under this scenario the zdp blades are fantastic.

If you use the blade for heavy cutting and significantly dull the edge, then it's a different story for me. zdp is hard stuff and it takes a lot more time to resharpen or reprofile the zdp edge than say a SYKCo Yard keeper’s blade which is tough and easily resharpened and even reprofiled. Also if you use the zdp hard IT WILL CHIP the tip or edge. Then it's just plain tough for the average owner that does not have a grinder or belt sander and/or the skill to use them. You basically would have to send the knife in to have the edge reprofiled or sharpened. Most folks don't want to give up their EDC that long.

Most of us on the knife forums have many different types of knives and steels, and I personally use many, many of my knives. I have one of every one of the Spyderco zdp knives and I love them because I only use them for a lot of light to medium cutting. They are great to carry because they are folders and compact and the handles are made of materials that are light and tough. But if I need a knife for heavy cutting that might include prying or impact, then I use a SYK, SRK or Busse. If I had to pick just one small blade for everything that I do with a knife, I would not pick the zdp steel for the reasons above.
But for the average person that uses a knife for cutting a lot with everyday light to medium usage, the zdp knives are great IMO.