Feature Richnesss
Some of the world's best programmers and consultancies have a vested interest in the development of TYPO3 and have formed a strong community in response to that need. When ideas are initiated, they are openly discussed among the group and quickly integrated within the next version of the software or built into an extension.

Usability/Ease of Use
A CMS can only be successful if content editors and administrators are willing to use it. Most of the time you have to choose between a CMS that is easy to use or one that has the functionality you need. With TYPO3, you won't have to make that decision since the software already maintains a good balance between the two.

Enterprise Platform
TYPO3 is open source, available under the GPL license and free to download. With commercial systems, the cost of license fees can add up quickly as you add content editors, software extensions, servers and databases.