Hi,
You can go with Sharepoint for your business requirements on Intranet environment (ofcourse Internet also).
Advantages:
1. Since it recommends AD integration, there is tight security and all authenticated users in the organization can access the site.
2. Easy to install and utilize.
3. Gives good look and feel. Also you can customize as per your requirements / you can use built-in themes.
4. Provides many out of box features useful for an organization to publish information like, Announcements, Events, News, Calendar, Contacts, Document libraries, Picture Libraries, Discussion forums, Surveys.
5. You can also integrate the existing sites with the sharepoint site.
6. Portal wise search enables users to search for the content.
7. Using Windows Sharepoint Services, teams can create their own site for sharing information among them.
Hope this information is useful to you to take decission.
*Rate this article if it is useful.
Kris.