I'm on the fence about this. I've worked in an organization with product managers for nearly 8 years now. The good product managers know how to drive the product (and understand the market, something engineers may not be interested in) but allow engineers to do their thing. The not-so-good product managers get caught up in small details (like what color to paint the bike shed) and attempt to tell engineers how to implement features.
About 18 months we were acquired by a larger company which had product management in one business unit but not another. We were allowed to keep our PM structure. 18 months later, guess what units have the highest revenue? And guess what unit bled money?
About 18 months we were acquired by a larger company which had product management in one business unit but not another. We were allowed to keep our PM structure. 18 months later, guess what units have the highest revenue? And guess what unit bled money?