I like EDIS and COP, but unless I'm missing something, the distributer guy is using flawed understanding to scare you away from a distributor. The distributor has some drag, and so does the cam. That's why a fixed tensioner on a timing belt motor works even if (when) the belt stretches. the drag keeps the slack due to lash on the non tension side. As long as the engine is turning, the lash is absorbed by the drag, unless the engine seizes or you miss a shift, at which point who cares what the actual timing is. This differs from driveline lash, the momentum of the car is greater than the drag, unlike the momentum of the distributor shaft.