I've owned three Pilot Knight BPs for a few years now, and I recently saw a silver Knight at Peyton Street Pens for a good price. It now joins my group of three matte black and chrome Knights as smooth-writing daily use pens.
The Knight reminds me of the Cross ATX in shape and is a well-crafted alternative to that pen. With 2 ATXs in my collection (one USA in matte black and one bright blue China model), the purchase was easy for me to justify to myself.
Key features on the brass barrel Knight are the smooth twist activation mechanism, use of fairly common Dr. Grip BP refills, and a hinged clip (unlike the questionable clip on the ATX) that fits in my shirt pockets well, regardless of the fabric or thickness.
Alas, the Knight is discontinued by Pilot, but the general shape lives on in the cheaper Metropolitan (which I also have a few of). Not a collectors pen for sure, but a nice writing tool that I enjoy.