I just got a Tenacious a few weeks ago as my first Spydie. So far, I love it. I'm not saying it is perfect but it works great for me.
Fit and finish is very nice. Grind lines are clean and even and the factory edge was nice and consistent. G10 scales are shaped nicely with no sharp edges. The jimping is sharp and, with the combination of the thumb ramp, makes for a really secure grip. The blade shape is very attractive and has proven very functional for EDC purposes. All metal is polished well.
The FFG makes it an awesome slicer and the knife was shaving sharp straight out of the box. I haven't used mine super hard though I have cut a little cardboard with it and the edge seems to be holding up great.
The Spydie hole is pretty large and is easily accessible. The detent is such that you can "load" the blade a little before deploying and it just rockets out. Lock-up is perfect. No play at all in any direction and the liner lock is adequately thick IMO. The knife feels very sturdy and yet only comes in at 4oz.
Now for my few complaints...
The knife was too stiff on deployment out of the box. This was easily remedied by backing off the pivot screw a touch and I still have absolutely zero blade play.
The blade is not centered exactly. It is off center in the direction of the non-locking side. It isn't by a lot and it isn't anywhere near contacting anything. It's definitely not something that would keep me away from this knife.
The clip is ridiculously stiff. The first few times I carried the knife, it was pretty hard to pull it out of my pocket but it has gotten much better and it doesn't bother me at all now. The knife is going to stay put but it comes out pretty smooth now.
The G-10 is not super grippy. It could definitely be more highly textured, but the handle shape, thumb ramp, and sharp jimping combine to lock the knife in tight.
You won't be disappointed by the Tenacious.
Here are some pictures of it straight out of the box with the Bug that I bought at the same time.
