AdaptCMS is a PHP Content Management System, available now for 7 years. The 2.x line was a new generation of software, heavily upgraded and cleaner code over the 1.x line. Starting with the next line, 3.x, AdaptCMS utilizes such libraries as jQuery, cakePHP and bootstrap.
Realizing how important and useful a framework could be, I researched the various ones and went with cakePHP. Along with integrating base bootstrap (with some customizing), we also have made good (but not over the top) use of AJAX, jQuery and a CMS that is overall a lot cleaner, better and more flexible than ever before.
A content management system is a piece of software that lets you install it and if done right, allows users to easily manage their website from the comforts of a (hopefully) easy-to-use software. This means that you can manage content (a.k.a. Articles/Posts), you can manage users, the appearance of the site and it usually should not require someone with knowledge of PHP to do this. Most, if not all, websites that you visit that have content (CNN, reddit, etc.) use some sort of Content Management System.
This isn't necessarily a "Yes" or "No", I would say that it depends. I would say that feature wise - it shouldn't be a concern. If it's an enormous website, I wouldn't call AdaptCMS "Enterprise Level" - you would be better off with a custom written CMS. But for gaming sites, blogs, music, just about any kind of content site - you should have no problems adapting.
What I would highly advise is if you are interested, take a look at our Plugin database and Feature list to see if it has everything you need. Then, you should checkout the demo to see how it operates and if you like it or not. And of course, send us a message and we'll answer any questions you have!