I am using them for basic auto categorizing and have reconfigured most of my collections into the new "tag collections" to auto collect items by tag.

So far this is really working great especially from the F8 quick entry box because then I can capture and tag in one action and then let Yojimbo software elves do the sorting for me.

Side note: Although the new tagging feature in Yojimbo could use improvement (tag collections offering a "any/all" option for instance), I think the way they have implemented the UI of the "1.0" version of this feature is really elegant. I really think it is one of the slickest apps for the Mac.