Paje I tried Drupal right when i was starting web development, CCK was a very good thing but the fact that you had to know a bit of php drove me off, then i came across Wordpress, this was even worse because back then it was really a blog, you either had pages or posts or custom fields, (they added custom post types later, by then i had dropped it as well), but still you need to know php to use Wordpress as a CMS's because deep down its still a blog to its core.
Then i found my perfect CMS, ExpressionEngine, It is not OpenSource (you have to pay 300USD license fee per site but you can charge that to the client) and trust me, the money you pay is worth it. You can create any kind of website / app without touching any php code, you just need to be a good designer and the best thing about it is you don't have themes so your website will never look like another website because you design everything yourself.
Why is it a great cms?
- Custom content types can be created by a mouse click and displaying them on your template will not require you to write any php code
- Relationships are built in, if you need to create related contents, just create a content of type relationship
- You can create an API without any php code, If you need your templates to return jSON data, you got it in ExpressionEngine
- Memberships are built in
- You can extend it with add-ons (commercial & free addons are available)
- Great support because it is a commercial product, paid support staff are always there to help
- Unlike other open source php projects, it was created on top of codeigniter, a great framework on its day that was created on solid programming principles ( OOP, MVC etc)
- Secure and will definitely add speed to your work.
An alternative CMS is CraftCMS, this is another gem of a cms, the guy who created it has several ExpressionEngine's top selling add-ons, in short Craft was inspired by ExpressionEngine and it has one of the most beautifully designed backend you'll ever see.
There's a lot of places you can learn how to use ExpressionEngine and Craft, if you need help just drop me an email and i will help.
All the top web design agencies in the world either use ExpressionEngine or Craft. By the way i am not getting paid to say all this but i have been around long enough and used most of those CMSs especially for all the small projects we do at our lab so i'm definitely qualified to give opinions on this topic.