I just got my tenacious today. I'm gonna carry mine left handed as the BG-42 millie refuses to budge outta my strong side right pocket. After switching the clip to left side tip-up I was pleased to find the thumb guide on the now exposed slab. Also, I can unlock the knife with my left index finger forwarn on the lock and drop the blade so that the kick hits my finger instead of the live edge much the same as can be done with a cento 4 or Yojimbo.
The knife did not arrive Golden or Seki sharp but it tuned up nicely on the sharpmaker. I'm not sure how well the 8Cr13MoV will retain its edge (or really care as this knife will be carried for protection) but it did gunk up the sharpmaker rods much more readily than the other common Spydie steels.
Seems like a great knife for the money!