I have the P-carry in 10mm. It's a power packed handful!
SOlid, reliable. The DA trigger could be better but lubeing it helps.
I also have the full size, steel framed witness in 45 acp. The DA trigger is very smooth on this one. It's a heavygun, but easy to shoot.
The only drawback to the Witness design is it's lack of a hammer drop lever. You can carry them cocked and locked like a 1911 and your first shot is SA. If you want to carry it hammer down with a DA first shot, you'll have to carryfully and gently lower the hammer using one hand on the trigger and the other hand on the hammer. Always a bit dicey, but I've done it for years w/out mishap.
You can change calibers easily w/ the witness pistols by simply buying a slide/barrel combination in the caliber you want...fairly inexpensively.