Regards the Pentax Lab software, I have it installed and used it as a test once. I suppose it can replicate the camera's JPEG rendering if you work at it, but why bother?
It depends on if the person has forked over the grand for CS, doesn't it?
I've been using Photoshop for so long that its price is no longer relevant. I've tried virtually everything else out there and nothing else works as well for me.
Godfrey