ExpressionEngine doesn’t dictate how you build sites. You have complete control over the output of your content and HTML.
Third Party Developers
There is a lot you can do with EE out of the box but the Add-ons push ExpressionEngine to the very next level
There are numerous custom field options including relationships, videos, maps, subscriptions, images, events, products, audio, tutorials, descriptions, excerpts, pages, dates. These can be easily mixed and matched to produce powerful content options.
Web Moving Forward
Content Strategy is improving the web and has made us think as content as “chunks” rather that web pages. There is also to explosion of mobile and large screen devices which has changed the way how our content is used and consumed. With custom fields EE fits very well into these changing ways.
Empowering small and large agencies
Only a decade ago a small army of developers was required to build what one skilled developer can now do with EE. That said ExpressionEngine is utilised by large agencies including the HappyCog, The Nerdery, Digital Surgeons and Viget. EE powers some very well known brands including the BBC, Nike, Sony and Ford, who are just the tip of the iceberg.
EE has reputable security record. There have been security updates to the software but as of 2013 there have been no major security breaches to date. The 'hacks' i've seen have been more down to the server and hosting environment.
What can EE do?
It's more of what it cannot do. EE is a content management system but by being able to take payments and power member sites as only a number of options, it can do so much more than just content. EE is not really suited to low budget sites that you are looking to make a 'quick buck', due the way it's built for custom solutions.
EE allows for very flexible, scalable and unique sites to be easily controlled by your clients. Building sites with ExpressionEngine is hugely satisfying and you get a real sense of achievement building sites that your client's love.. Working with it is great fun.