The ideal form of government for getting anything done on a small scale. Its success, however, depends on the following circumstances:
A prime example of a wildly successful benevolent dictatorship is an artistic group and their leader; it could be a choir the choir director, a play and its director, or a student and teacher. These are situations which work extremely well given the right dictator, and simply fall apart if there isn't a strong sense of leadership present.
One might think that these groups could work even better given the right Commonwealth Model. Everyone would have a say, votes could be taken if there is widespread disagreement, the group would be stronger for relying more on the individual and less on authoritative mandates. However, experience clearly shows that this is not the case. A vote leaves things strangely unresolved. Precious time is wasted quibbling on minor points that could be solved in 1 second by a knowledgeable and experienced leader. The leader is always free to ask for input, but will often refuse it when they already have a good idea of what they want.
Also, if the dictator is personable, the group often has a feeling of pride and inspiration in having the privilege of working for them. If nothing else, there is always a respect for their abilities that causes the group to value their opinions and respect their decisions.
A commonwealth could decide what time a rehearsal starts and ask everyone to be on time, but this almost invariably leads to people waltzing in whenever its convenient for them. However, when a dictator says "don't waste my time, and I won't waste yours" and means it, people magically manage to arrive ahead of time.
The difference between the clumsy commonwealth and the focused dictatorship is very dramatic and very noticeable if you watch them side-by-side. It's amazing the work ethic and sense of purpose that the right dictator can give an otherwise disorganized and scattered situation.