In order to build a well-designed and high-performing product, a business needs to have a comprehensive understanding of what the consumer wants. Targeting the right market, the right type of customer, as well as who the competition is in the space, is critical to survival. This is what a product manager excels at doing, and is worth his/her weight in gold for a business.
Product managers oversee the evolution of a product, from concept- to development- to market. Product managers find out the (not so simple) answers to the who, what, why, when, and where of a product and then create that product to directly answer customer needs. They also keep a company's brand ideals in mind as they align the product characteristics to match. Doing this greatly increases a company's chances of success since having this type of information can only mean creating tailored solutions for customers. A product manager will listen to the 'voice' of the market through research - this consists of gathering, testing, and analyzing data, getting direct customer feedback, and by using business intelligence through internal sales and customer service teams.
Marketing managers have different responsibilities in regards to presenting a product. Their focus is on strengthening the brand and boosting sales, which involves developing and implementing a profitable strategy to promote a product or a product line. They use various product marketing techniques (such as ads, email campaigns, webinars, presentations, etc.,) and they work with design, product, and sales teams to coordinate various processes and channels.
Although the two managing roles are different in many ways, they intersect and collaborate on a daily basis. Marketing and product managers work closely together with the goal of defining and delivering a great product to the customer.