Well... although this isn't what I'm after at all, I'm quite impressed. It's blazing quick, even when doing batch optimizations. The optimized files look good as well. However, it is truly automatic - no user controls for anything, so not really suited for my purposes (I need to be able to selectively remove parts of a scan). After I realized this, I downloaded a trial for Ashampoo PhotoCommander 5 on the assumption (only partially correct) that Photo Optimizer is a streamlined, dumbed down version of PC's editing tools. It was impressive as well. It's a small download for what it does and is also blindingly quick. Unfortunately, it doesn't do what I'm after, either!
What I'm after is something that will allow me to remove artifacts from scans before converting them into pdfs (you know, the patina that overlays the image itself, splotches, etc). So, for example, I need to be able to select a colour and remove all instances of it from a file. Paperport also has an automatic straighten tool that is really easy to use (and very useful when dealing with scanned documents). I can do both tasks in PaintShop Pro but the bloat - it takes over a minute to load and once I'm there it's not as easy to use - is a turnoff and I don't find it does as good a job. If Nuance/Scansoft marketed a standalone version of their scan editing application, I'd buy it in an instant.
EDIT: Just send a PaperPort "feature request" to Nuance BEGGING them to consider releasing a standalone version... Of course, I am convinced that something similar already exists, and probably as a freeware/open source project, but I haven't found it yet