Best canti's ever, though TRP Revos were close. The key features are 1) road bike shoes, and 2) varying spacers that make them work with any (in the relevant range) stud spacing and rim width. Also, the ability to release the springs so easily is a big help.
As noted, you can use them with any straddle cable and hanger, but I have had no trouble setting them up with their standard hardware. First be sure you have the right spacers/washers so the pads are contacting the rims with the shoe-mount arms perpendicular to the ground. Then run the cable through the round thingie down the plastic tube to the arm with the cable clamp. You should just be able to fit the "quick release" end of the hanger into the other brake arm recess, and the plastic tube should cover the cable all the way to the brake arm. After getting the cable adjusted right (and not before!) bend the cable out over the little arm at the back of the round thingie and into the slot between the arm and the round thingie. (Sorry, that's the best description I can come up with.)
Pad setup is incredibly easy. Release the spring on the side you're adjusting, so the spring on the other side pulls the pad you're adjusting to the rim. Loosen the bolt, move the shoe to where you want it, put a credit card between the trailing end of the pad and the rim, and tighten the bolt. Replace the spring.
I have them on a 1983 Santana Tandem (first time I've ever had confident braking on that bike), three Sam Hillbornes, and a Heron Touring. I highly recommend replacing the stock CX50 shoes with replaceable cartridge shoes and some good pads. The pads on CX50s are shockingly bad in the wet.