There are several advantages to matrix management, including:
- More authority for the Project Manager
- Only selected and adequate resources are assigned to the project
- It's a step towards a projectized organization, where any activity inside the company is treated as a project, with a clear start and end date.
Now for the disadvantages:
- More conflicts between Functional Managers and Project Managers, because Project Managers will feel emboldened by their increased authority.
- Overhead and redundancy in lower management (e.g. why have a Functional Manager when Project Manager is doing all the job).
- Complexity in the organizational structure of the organization (multiple managers, communication overhead, etc...)