Some might argue that building continuity is more important. There is some truth to that statement, but it's far less important than people think. Programming is a commodity task--it's just easy grunt work. You can hire anyone to do it. That's why I hire freelancers and outsource all the programming details. You can easily drop people periodically and hire someone new; that keeps the cycle of fresh minds working on a project. You can work the fresh freelancer harder, get the most out of him as possible, and then bring in someone new again.
The management is the part of the team with the vision and the ideas. The PHB is where the continuity comes from. With hands on micromanagement, the PHB is familiar with the entirety of the project and can assign the detail work to the constantly changing worker pool. The ever changing company workforce keeps the company on the cutting edge.