Choosing a CMS determines how easily the company will manage content and how much the website will cost it in the years ahead. The decision should not be made on the basis of how popular the system is, but on four criteria: who will actually edit the content and whether they can manage it without a developer, what features will be added and whether the system can support them, how it stands on security updates, and finally how available on the market are people who know how to manage it. The last point is the most common source of problems with less widespread systems, because the company remains dependent on a single supplier. The comparison should also include the option to export content, since that is precisely what determines whether a future migration will be manageable.
See also: Ownership of the website and source code, Website migration without losing rankings, Website maintenance and updates.