I would say the greatest Cub manager of all-time was Joe McCarthy. Naturally, the Cubs fired him and he would only go on to win something like 7 world series titles. Although Charlie Grimm, who would follow him a couple of years later, was fine manager in his own right and led them to their last NL pennant (4 total). I know some of a certain age might be partial to Leo Durocher. In recent years, it has been such a revolving door, it is hard to get a gauge on any of them. There comes a point where it is not so much the manager as it is the organization. I'm kind of partial to the college of coaches though, because eight minds are better than one.