Pesan, welcome to the forum. I'm sure your broken cable was just an odd defect, nothing you did would have caused or prevented it. If you have to wait for a replacement, you can probably just remove the cable and continue to use the Drive on a temporary basis though it may not operate quite as smoothly.
Bruce, I think the biggest improvement with the current drums and chain/cables is the drums themselves. They add a lot of stability to the drum - pedal crank interface and have greatly reduced the potential for skipping out of the selected pedal position. They also have glass-filled nylon for greater strength and extended wear on the the drum shaft. The main improvement relating to the cables that they no longer have to flex
at the swedge, so the reliability of this joint has improved. The third advantage is slotted cable holes in the drums which make cable adjustments much easier. The one disadvantage of the this arrangement is the tendency for the Nyloc adjusting nuts to loosen up after a couple of adjustments, so the use of Loctite Blue (or new nuts) is recommended to keep everything in place. IMO, the best time to consider an upgrade is if and when your old style drums cause any problems. I don't think Pesan's cable break is related to the new design.
