Nice bunch of knives.
I have had, for over 25 years, two Spyderco folding knives. A Delica, and a Endura. They are good quality knives made early in Spyderco's start up. The knives made today are better I think, better material in the handles and the metal clips instead of the early knives molded in clips. The Seki made knives are still the same quality steel though, from what I can tell.
Mine were seconds, obtained from an employee, and they had the molded in plastic clip ground off. That didn't bother me at the time, but today I would prefer a metal clip on them. Visually mine look like the Tenacious you have.
What I like about Spyderco knives, besides their quality and design, is the number of models they have made and the wide variety of steel they have used in their blades.