There is a camera profile color difference in Pro 6. Very minor and a default can be set by the user. Normally I give it a +.25 exposure increase.
I use Pro 6 sharpen for 'Capture' sharpening, I use a plugin in my external editor for out put sharpening. Big difference.
Noise reduction is fair, i use it only to remove noise generated by the capture sharpening. Once again I use a Plugin.
The catalog feature in Pro can't be beat, If you look at an image or folder, it's imported. Categories and Keywords are simple to assign.
Things I like : Non-destructive editing, Lighting Tool Tab, Color Tool Tab, Clarity, Vibrancy. With Lighting you can use your mouse and
drag with either left or right button held down to change lighting zones.
I've used Pro since 2.5. Pro 6 is the best yet for color and tools. It's price is cheap now probably because Pro 7 is coming soon. They
always drop the price before a new release.
Disclaimer
I judge a raw converter on how well it matches the Pentax Programs output. If it takes WAY too many adjustments to get
close to Pentax it's not worth it to me. Pro 6 works pretty good.