My opinion? I am the starter of saying, "I rather have a small team of people I can trust than a large team of people I don't know" so naturally I would say that it is better for everyone to be the boss of their own job - though you always need someone who is above others. IF someone decided to be lazy for awhile, someone needs to point him at that.
There should always be at least one member of a project that has a leadership ability, though unfortunately, being a good leader is something which is much harder than most people think. Most people aren't able to take on the responsibility and therefore I am more fond on multiple leaders at the same time. Oh, and before anyone asks, I can't take the responsibility of leading an entire team either.