I use Plone to manage more than 30 websites: corporate website, local websites, blog and company intranet and it fits for all needs I had. I have a complex infrastructure to manage all resources that are used across the different websites (events, PRs, articles, resources, training courses) to avoid duplication of contents. I used Plone over more than 8 years changing multiple times the design, structure and overall organization and I've not had big issues or features I couldn't develop. I manage more than 10 languages, including Russian, Chinese and Japanese. I am totally autonomous to manage my contents including combining the different elements using multiple layouts (defined with the agency). So I have the flexibility to create different pages without asking to the IT. I only need the designer/developer if I need to create a new layout or a new feature. We easely integrated Plone with multiple external systems: Marketo (Marketing Automation Tool), Microsoft Dynamics (CRM), Mediadrop (video library). Plone is open source so you don't have to pay annual fees, is really important to select the right web agency that can customize Plone to fits your needs.