Although they were not designed as "tactical" folders, Delicas and Enduras make excellent defensive tools. (Good ergonomics, cheap, readily available, lightweight, decent blade geometry, legal to carry.)
There are a number of respected instructors and professionals who give them high points. And several defensive systems have evolved specifically around them. Erik Remmen (who developed the original Clip-It course), had Spyderco factory-dull a dozen or so pink Delicas as drones a number of years ago.
Joel - who is very biased when it comes to Delicas