Having just acquired PK Sharpener, I'm undertaking the project of comparing it to my current workflow (Focus Magic + my midtone sharpening action). Since PKS has a plethora of options and I've only had it a short time, take the results with a small grain of salt, since I'm not nearly as intimately familiar with it as I am with my current workflow. If anyone more familiar with PKS notices any glaring errors in the settings, feel free to point them out.
The test image is crop from a 1Ds capture of downtown Trier, taken on an overcast day. DR is just barely within the limits of the sensor, and there is a lot of fine detail and a bit of noise to make getting the detail without too much noise a bit of a challenge. No noise reduction or sharpening was applied in ACR or afterward.
This post's comparison is limited to capture sharpening; PKS vs Focus Magic. PKS settings were as follows: Expert High Resolution Digital Capture, Medium Width. Focus Magic's settings were: 1 pass 2 pixel radius, 25%, then 1 pass 1 pixel radius, 25% source set to Digital Camera for both passes.
Some points of interest:
In the bottom left area, the Merkur Spielothek sign is brought into clearer focus by FM than PKS, without the noise in the wall above the sign being accentuated as it is with PKS. In general, PKS accentuates noise much more than FM, but focuses sharp edges less well. When the PKS smoothing layer is turned on, the noise accentuation goes away, but edge sharpening becomes even less effective. PKS appears to be USM-based, whereas FM actually attempts to mathematically unravel the effects of blur. FM appears to me to do a significantly better job overall of undoing the effect of an AA filter than PKS and USM-based sharpening in general, which is why I don't even use my own action for capture sharpening.