I bought both a PE and an SE version of the Caly3, and IMHO, the Plain-edge version is superior.
Why? Well, I feel that the leaf-shaped blade with the full-flat grind simply lends itself more to sweeping slicing cuts, which I feel the serrations hinder. I don't think that the serrated version is a bad knife by any means, I just prefer a plain edge in a leaf-shaped blade.
That got me to thinking, what other blade profiles lend themselves to PE/SE? For one thing, I realized that serrations are basically mini-hawkbills; trapping the target so that a pull-cut can be done (Any thoughts, JD or Starling?).
I realize that there are some people (Spydutch...) who prefer Serrations no matter what the knife, and other people who love a knife in one edge version, but don't love it in another version (like me with my dislike for the SE version of the Caly3).
So, what I bring forward is this: Which knives do you feel lend themselves to PE or SE (or CE...), and why?