I constantly get asked which CMS is best. My usual answer is "They're basically all the same, it depends entirely on your requirements"
You wouldn't ask a builder to make a house and then tell them which type of concrete they should use
The choice should be up to the agency/development team of which CMS to use. Theres several reasons for this but the main reason is if they're doing they're job properly they will gather your requirements and evaluate a CMS from those requirements. Its your job to make sure the requirements and expectations of the chosen CMS platform are properly communicated. Remember what CMS stands for (Content Management System) so by definition the best CMS will have a balance of structured content but still doesn't block you from creating and modifying the items that you need. Another important point to remember that "The Best CMS" in the wrong hands can be turned into a poor bad CMS.
Lets go through the different types of CMS' that are available.
The first and still often implemented is a bespoke CMS build, with the usual punch line of "Oh we'll customise it to your needs" Heres the dirty little secret. Using a bespoke CMS is two jobs: building a CMS that allows the usual functions of a CMS. Things like easy page handling, file management and media library the list is endless but most importantly adding new features whilst also keep up new features up to date and having update and migration paths between different versions and new features is a complex job and should be left to a dedicated team. The second job is then to create the front end and add the features that the business require such as integration with other systems.
Second option is Open Source (Joomla, Drupal, Concrete 5 and Wordpress (Although technically wordpress isn't a CMS its a blogging platform)
There are some great CMS that are open source but usually suited to smaller volume websites. Lack of on demand support/bug fixes creates a particular risk. For many companies, especially larger ones but there is certainly a time and a place to go open source a good agency/developer should be left to make this decision.
3rd Party CMS (Kentico, Sitefinity, Sitecore)
This comes with an upfront cost that many find hard to swallow, I usually prefer to use one of these as it they have great foundations and support for a well built and easy to use website.
Features such as:
‘Simple’ or easy to use interface Workflow Media Library Page and URL Handling Membership Functionality Pre built webparts or modules provide are important as long as they are easily extensible or modifiable. Multi site under one server instance allows Media Library and assets to be shared
Kentico provides an extensible and flexible foundation which make it easier.
Focus on structured content - Document Types Webparts provide extensibility Improve on previous learning within the same site foundation Learning a new CMS admin etc.
Redundancy servers would be recommended, depending on the budget however there are cheaper ways than just hosting multiple servers.
Put simply a CDN creates a multiple copies of site asset files in key server locations around the world in a cost effective manner so page load times are quicker. Further reading on CDN networks (http://www.webperformancetoday.com/2013/06/12/11-faqs-content-delivery-networks-cdn-web-performance/)
Take a look at Amazon Cloudfront or Maxon CDN
Unfortunately there are no short cuts any CMS that is chosen will never make everything just work together.
The job of a CMS is to make it easy/quick for webmasters and other stakeholders to manage the content on the web. So that when users are viewing the website there is a consistent feel, webmasters don’t HTML and design a webpage instead they have a selection of templates to chose from and then enter the content in a structured format.