How does PKS2 relate to the sharpening in LR3? Or, since PKS2 has come out after LR3, are its routines that much more "advanced" than LR3?
Actually, I can't answer that completely for NDA reasons (with Adobe) and for competitive reasons for PixelGenius...
Since I am involved in the development of both PhotoKit Sharpener 2 with PixelGenius and with Adobe for the development of ACR/LR I have to walk a very fine line.
I can tell you that we (PG) worked with Adobe to incorporate PKS Output Sharpening concepts inside Lightroom 2.x (I don't remember what version). I also fulfilled Bruce Fraser's consulting contract to improve the capture sharpening in ACR 4.1 and LR 1.1 (I think that was the LR version it first showed up in).
I've also continued to work closely with Eric Chan (the mad man!) to keep improving the output sharpening as well as the capture sharpening and noise reduction of ACR/LR.
And I worked with Mac Holbert who is the product manager and chief action writer for PKS 2.
I can't get into how each thing does its thing if you know what I mean...I will say I don't think it matters whether you do output sharpening in PKS 2 or ACR/LR. To me it's really a workflow issue not a technical issue. As far as I'm concerned, using either still means PixelGenius has touched your pixels :~)
Whether to use ACR/LR or PKS 2 for capture sharpening is again more of a workflow issue. PKS 2 is now pretty automated. ACR/LR needs careful adjustment. But it's an either or proposition...you should only use one OR the other.
The one thing I will point out is PKS 2's Creative Sharpeners kick ACR/LR butt...(but that's just a personal opinion that's prolly a bit biased).