Hi Daniel, you need to know quite abit about the current maturity of the project management process within an organization before attempting a Project Server implementation. Then you need to consider the sensitivity of the project data since it will become easy to access for anybody in the project team if proper configuration steps are not taken. After that I would consider your enterprise reporting needs. Followed closely by an understanding of how your users will manage the data entry. Project Server can be overwhelming but it can also be extremely beneficial. Hope this helps, contact me if you need more info on this topic.
